ORDER AND JUDGMENT *

This | case presents the question of whether a plaintiff’s death moots his request for an injunction ordering certain officials of the State of Oklahoma to determine him eligible for Medicaid benefits. We answer yes. The claim for injunctive— that is, prospective—relief is moot because there is no concrete threat of a continuing or repeated injury to the plaintiff-appellant, Alfred Pecha, because he is dead. Any harm to Mr. Pecha lies squarely in the past.

Mr. Pecha’s attorney-in-fact, his niece, Patty Pecha-Weber, argues on appeal that Mr. Pecha’s death does not moot his claim for injunctive relief. She further argues for an order for an award of retrospective Medicaid benefits under 42 U.S.C. § 1396a(a)(34). However, because we determine that Mr. Pecha’s claim for prospective injunctive relief is moot and Ms, *842Pecha-Weber concedes that any order of retrospective benefits must be ancillary to such prospective relief, we can find no error in the district court’s dismissal of the case. Accordingly, we affirm the district court’s judgment.

I

Mr. Pecha initially applied for Medicaid benefits in early July 2014. Acting on Mr. Pecha’s behalf in that administrative matter—and throughout his subsequent judicial quest for Medicaid benefits—has been Patty Pecha-Weber, Mr. Pecha’s niece, whom Mr. Pecha appointed his attorney-in-fact in February 2011. After Mr. Pecha failed to obtain a determination of his eligibility for benefits, he brought suit in the United States District Court for the Western District of Oklahoma alleging a failure to timely provide such a determination. Specifically, invoking 42 U.S.C. § 1983, Mr. Pecha sued Ed Lake, the Director of the Oklahoma Department of Human Services (OKDHS), and Joel Nico Gomez, Director of the Oklahoma Health Care Authority (OHCA) (collectively “Defendants-Appellees”). As reflected in his amended complaint, he requested both injunctive and related declaratory relief. The requested injunction would have. required both that Defendants-Appellees certify Mr, Pecha as eligible for Medicaid benefits and that the State pay three months’ retrospective Medicaid benefits.1

On July 21, 2015, the district court granted in part and denied in part the Defendants-Appellees’ initial motions to dismiss. The court dismissed Mr. Pecha’s claim for a declaratory judgment on the basis of Eleventh Amendment immunity. However, the court ruled that the payment of three months’ retrospective benefits could be ordered and “would not run afoul of the Eleventh Amendment in light of 42 U.S.C. § 1396a(a)(34).”2 Aplees.’ Supp. App. at 6 (Order, filed July 21, 2015). The court permitted Mr. Pecha’s claim for in-junctive relief to go forward.

Mr. Pecha died on March 6, 2016. The Defendants-Appellees subsequently filed a suggestion of mootness and a motion to dismiss. In her response brief, in addition to arguing that the case was not moot, Ms. Pecha-Weber—whom a state court in April 2016 had appointed the personal representative of Mr. Pecha’s estate—sought to substitute herself and Mr. Pecha’s estate as the plaintiff. The district court, however, dismissed- the action concluding that “the death of Mr. Pecha renders prospective injunctive relief impossible and therefore, the incidental back benefits sought cannot be tied to any prospective injunctive relief,” Aplt.’s App. at 469 (Order, filed May 18, 2016), Though it did not explicitly address the matter, the court’s *843dismissal of the action effectively denied Ms. Pecha-Weber’s motion to substitute parties.

Ms. Pecha-Weber—in her role as attorney-in-fact—now appeals, arguing that prospective relief is still possible in the form of an injunction requiring the Defendants-Appellees to determine posthumously that Mr. Pecha was eligible for Medicaid benefits. Such prospective relief would in turn permit the district court to enter an order for the payment of retrospective Medicaid benefits under 42 U.S.C. § 1396a(a)(34).

Notably, Ms. Pecha-Weber does not argue on appeal that the district court erred by failing to grant her motion to substitute. Nor has she sought to substitute herself on appeal as plaintiff-appellant, in her role as personal representative of Mr. Pecha’s estate, by filing a motion under Fed. R. App. P. 43(a). Thus we conduct our analysis as though Mr. Pecha were the sole plaintiff before us; any contrary argument that Ms. Pecha-Weber could have (but has not) raised is waived. See, e.g,, Kannady v. City of Kiowa, 590 F.3d 1161, 1175 (10th Cir. 2010); United States v. Abdenbi, 361 F.3d 1282, 1289 (10th Cir. 2004). Consequently, as she did before the district court, Ms. Pecha-Weber litigates this appeal solely as the attorney-in-fact of Mr. Pecha. And, significantly, Defendants-Appellees do not question her authority to do so. Cf. Bush v. Remington Rand, 213 F.2d 456, 464 (2d Cir. 1954) (concluding that “the defendant, by its long delay in raising the issue, had waived its right to object” to failure to substitute in the district court a proper party-plaintiff upon plaintiffs death).3 With the stage thus set, we turn to the central question of whether Mr. Pecha’s death mooted this case, and answer in the affirmative.4

II

“[W]e apply a de novo standard of review because the case presents a question of constitutional mootness.” Rio Grande Silvery Minnow v. Bureau of Reclamation, 601 F.3d 1096, 1123 (10th Cir. 2010). Similarly, we review de novo issues of *844sovereign immunity. See, e.g., Governor of Kan. v. Kempthorne, 516 F.3d 833, 841 (10th Cir. 2008).

A

Ms. Pecha-Weber argues that the claim for an injunction to oblige Defendants-Appellees to declare Mr. Pecha eligible for Medicaid benefits is not mooted by his death. She argues that “[t]he District Court erroneously equated prospective injunctive relief to the payment of future Medicaid benefits.” Aplt.’s Opening Br. at 5 (emphasis added). Instead, Ms. Pecha-Weber posits that the prospective relief she seeks is “an injunction ordering” the Defendants-Appellees “to cease denying [Mr. Pecha’s] Medicaid application and coverage.” Id. at 26. That prospective relief would in turn “allow[ ] Pecha to receive past Medicaid benefits pursuant to 42 U.S.C. § 1396(a)(34) as relief ancillary to and in furtherance of the injunction.” Id, at 6 (emphasis added). The Defendants-Ap-pellees respond that the district court did not err because Mr.'Pecha’s death moots his claim for prospective relief; consequently, in their view, no ancillary relief can be awarded.

“Mootness is a threshold issue because the existence of a live case or controversy is a constitutional prerequisite to federal court jurisdiction.” Rio Grande Silvery Minnow, 601 F.3d at 1109 (quoting Disability Law Ctr. v. Millcreek Health Ctr., 428 F.3d 992, 996 (10th Cir. 2005)).5 The constitutional aspect of the mootness doctrine, at issue here, is related to the standing doctrine. Mootness is essentially “the doctrine of standing set in a time frame: The requisite personal interest that must exist at the commencement of the litigation (standing) must continue throughout its existence (mootness).” S. Utah Wilderness All. v. Smith, 110 F.3d 724, 727 (10th Cir. 1997) (quoting Arizonans for Official English v. Arizona, 520 U.S. 43, 68 n.22, 117 S.Ct. 1055, 137 L.Ed.2d 170 (1997)).

The relevant inquiry for a question of constitutional mootness is “have circumstances changed since the beginning of litigation that forestall any occasion for meaningful relief.” Id. Put differently, to moot a ease, “interim relief or events [must] have completely and irrevocably eradicated the effects of the alleged violation.” Bldg. & Constr. Dep’t v. Rockwell Int’l Corp., 7 F.3d 1487, 1491 (10th Cir. 1993) (emphasis added) (quoting Cty. of Los Angeles v. Davis, 440 U.S. 625, 631, 99 S.Ct. 1379, 59 L.Ed.2d 642 (1979)).

Where a plaintiff seeks prospective equitable relief, such as an injunction, we have recognized that, for purposes of the mootness inquiry, “a mere showing that he maintains a personal stake in the outcome of the controversy is insufficient.” Jordan v. Sosa, 654 F.3d 1012, 1024 (10th Cir. 2011). “[P]ast exposure to illegal conduct does not in itself show a present case or controversy regarding injunctive relief ... if unaccompanied by any continuing, present adverse effects.” Id. (omission in original) (emphasis added) (quoting O’Shea v. Littleton, 414 U.S. 488, 495-96, 94 S.Ct. 669, 38 L.Ed.2d 674 (1974)). Specifically, the plaintiff must show “susceptibility to continuing injury,” id., or a “likelihood of substantial and immediate irreparable injury,” id. (quoting O’Shea, 414 U.S. at 499, 94 S.Ct. 669); see Citizen Ctr. v. Gessler, 770 F.3d 900, *845906 (10th Cir. 2014) (“Because Citizen Center seeks only prospective equitable relief, past exposure to illegal conduct would not establish a live controversy in the absence of continuing ill effects.” (emphasis added)); Beattie v. United States, 949 F.2d 1092, 1093 (10th Cir. 1991) (“[W]hile a plaintiff who has been constitutionally injured can bring a[n] ... action to recover damages, that same plaintiff cannot maintain a declaratory or injunctive action unless he or she can demonstrate a good chance of being likewise injured in the future.” (omission and second alteration in original) (emphasis added) (quoting Facio v. Jones, 929 F.2d 541, 544 (10th Cir. 1991))); see also Randolph v. Rodgers, 170 F.3d 850, 856 (8th Cir. 1999) (“A claim for equitable relief is moot ‘absent a showing of irreparable injury, a requirement that cannot be met where there is no showing of any real or immediate threat that the plaintiff will be wronged ' again.’ ” (emphases added) (quoting City of Los Angeles v. Lyons, 461 U.S. 95, 111, 103 S.Ct. 1660, 75 L.Ed.2d 675 (1983))).

It is beyond peradventure that the dead are not susceptible to continuing or future harm; therefore, claims for prospective (e.g., injunctive) relief brought by deceased plaintiffs ordinarily are moot. See, e.g., Tandy v. City of Wichita, 380 F.3d 1277, 1290 (10th Cir. 2004) (“Beltz’s claims for prospective relief are moot because he has died. ... [Ojnce dead, he is no longer under a real and immediate threat of repeated injury. Thus, there is no longer a live controversy with respect to Beltz’s claims for prospective relief.”). Tandy’s holding leads ineluctably to the termination of this litigation. That is, Mr. Pe-cha’s death has mooted this case, which is based on claims for prospective relief— notably, for purposes of this appeal, a claim for injunctive relief.6

Ms. Pecha-Weber’s contention that this case is not moot rests, in principal part, on the assertion that there is an ongoing violation of federal law here—a requisite of an action for prospective equitable relief (e.g., injunctive relief) against state officials. See, e.g., Verizon Md. Inc. v. Pub. Serv. Comm’n of Md., 535 U.S. 635, 645, 122 S.Ct. 1753, 152 L.Ed.2d 871 (2002) (“In determining whether the doctrine of Ex parte Young[7] avoids an Eleventh Amendment bar to suit, a court need only conduct a ‘straightforward inquiry into whether [the] complaint alleges an ongoing violation of federal law and seeks relief properly characterized as prospective.’ ” (alteration in original) (quoting Idaho v. Coeur d’Alene Tribe of Idaho, 521 U.S. 261, 296, 117 S.Ct. 2028, 138 L.Ed.2d 438 (1997) (O’Con-nor, J., joined by Scalia and Thomas, JJ., concurring in part and concurring in judg*846ment))); accord Muscogee (Creek) Nation v. Pruitt, 669 F.3d 1159, 1167 (10th Cir. 2012). Ms. Pecha-Weber views the purported existence of such an ongoing (i.e., continuing) violation as a basis for distinguishing Tandy. She says that, unlike in this case, in Tandy no continuing violation of federal law could occur because the city of Wichita’s violation of the Americans with Disabilities Act (ADA) “occurred each time Beltz used [the] transit system,” Aplt.’s Reply Br. at 3, and he could not use it after his death.

However, even if the existence of an ongoing violation of federal law were material to the resolution of this action (which it is not, as explicated infra), Ms. Pecha-Weber’s attempt to distinguish Tandy on this basis would be mistaken. The violation of law that the plaintiffs alleged in Tandy was, inter alia, Wichita’s “continued use of its policy of giving drivers the discretion to deny wheelchair-bound passengers access to an accessible bus on an inaccessible route.” 380 F.3d at 1280 (emphases added). They “reasoned] that this policy violates the ADA.” Id. (emphasis added) (describing the district court’s entry of an injunction under this reasoning). In other words, the Tandy plaintiffs alleged that Wichita’s existing policy was noncompliant with the ADA—a violation of law independent of whether any particular plaintiff was able to attempt to ride the buses. Thus, instead of focusing on the bus-riding conduct of one individual, the Tandy plaintiffs centered their challenge on an existing policy that they believed represented a continuing violation of federal law. Therefore, Ms. Pe-cha-Weber’s attempt to distinguish Tandy for its ostensible lack of a continuing violation is mistaken.

More importantly, the existence of a continuing (i,e., ongoing) violation of federal law is immaterial to the resolution of this case. Irrespective of whether there is such a violation here, Mr. Pecha’s action still has to pursue “relief properly characterized as prospective,” Verizon Md. Inc., 535 U.S. at 645, 122 S.Ct. 1753 (quoting Coeur d’Alene Tribe, 521 U.S. at 296, 117 S.Ct. 2028 (O’Connor, J., joined by Scalia and Thomas, JJ., concurring in. part and concurring in judgment)), in the sense that it seeks to remedy a “continuing injury” to him, Jordan, 654 F.3d at 1024. And Tandy forcefully underscores what commonsense should already tell us: the dead, like Mr. Pecha, cannot suffer a continuing injury. Therefore, this action for injunctive (i.e., prospective) relief is moot.

B

Because of this conclusion regarding the mootness of Mr. Pecha’s claim for injunctive relief, Ms. Pecha-Weber cannot secure any other relief in this appeal. Ms. Pecha-Weber acknowledges that she ultimately seeks a district court order for the payment of retrospective Medicaid benefits under 42 U.S.C. § 1396a(a)(34); she characterizes this relief as ancillary to her requested prospective relief and so permissible under Ex parte Young, See Aplt.’s Opening Br. at 17-19.

Retrospective relief against a state is barred by the Eleventh Amendment. See Quern v. Jordan, 440 U.S. 332, 337, 99 S.Ct. 1139, 59 L.Ed.2d 358 (1979) (“In Edelman[8] we reaffirmed the rule that ,,. a suit in federal court by private parties seeking to impose a liability which must be paid from public funds in the state treasury is barred by the Eleventh Amendment. ... [U]nder the landmark decision in Ex parte Young, 209 U.S. 123, 28 S.Ct. 441, 52 L.Ed. 714 (1908), a federal court, consistent with the Eleventh Amendment, may enjoin state officials to conform their *847future conduct to the requirements of federal law, even though such an injunction may have an ancillary effect on the state treasury. The distinction between [the two] was the difference between prospective relief on one hand and retrospective relief on the other.” (citations omitted)); accord Buchheit v. Green, 705 F.3d 1157, 1159 (10th Cir. 2012).

The Supreme Court has approved of some forms of relief against a state that it has characterized as ancillary to prospective (e.g., injunctive) relief. See Quern, 440 U.S. at 349, 99 S.Ct. 1139 (approving the issuance of a notice “ancillary to ... prospective relief’ that “in effect simply informs class members that their federal suit is at an end, that the federal court can provide them with no further relief, and that there are existing state administrative procedures which they may wish to pursue. ... The class members are ‘given no more ... than what they would have gathered by sitting in the courtroom.’ ” (second omission in original) (quoting Jordan v. Trainor, 563 F.2d 873, 877-78 (7th Cir. 1977))).

But the problem for Ms. Pecha-Weber is that, even if this court were willing to assume that her requested order for retrospective benefits under 42 U.S.C. § 1396a(a)(34) could be characterized as ancillary to an injunction obliging the Defendants-Appellees to declare Mr. Pecha eligible for Medicaid benefits, such injunc-tive relief—as demonstrated supra—is not possible. Therefore, Mr. Pecha’s claim for retrospective benefits stands untethered to a claim for injunctive (i,e., prospective) relief. In other words, there is no injunc-tive relief to which the claim for retrospective benefits can be ancillary. Therefore, Ms. Pecha-Weber’s claim for retrospective benefits as ancillary relief must fail for want of a prospective predicate.

Indeed, Ms. Pecha-Weber concedes that she cannot obtain the payment of past Medicaid benefits unless it is ancillary to prospective injunctive relief ordering the Defendants-Appellees to determine Mr. Pecha to have been eligible for Medicaid benefits: “OKDHS and OHCA cited Green v. Mansour, 474 U.S. 64, 67, 106 S.Ct. 423, 88 L.Ed.2d 371 (1985) for the proposition that ancillary relief cannot be awarded independent of prospective injunctive relief. Pecha agrees. In order to receive ancillary relief, he must be entitled to receive prospective injunctive relief.” Aplt.’s Reply Br. at 5 (emphasis added).9

Ms. Pecha-Weber’s concession is determinative regarding whether an order of retrospective Medicaid benefits can survive the mooting of Mr. Pecha’s claim for prospective relief. It cannot. Mr. Pecha’s death mooted any claim for injunctive (i.e., prospective) relief. Thus, Ms. Peeha-Weber cannot seek ancillary retrospective benefits. The foregoing analysis disposes of this case.

Ill

In sum, this action for injunctive. (i.e., prospective) relief is moot because Mr. Pecha does not face a concrete threat of *848continuing or repeated injury to him because he is dead. This conclusion in turn bars relief in the form of retrospective benefits, which Ms. Pecha-Weber characterizes as ancillary to the requested injunction. We AFFIRM the district court’s judgment.