Gerald Grudzinskas appeals the district court’s dismissal of his 42 U.S.C. § 1983 complaint. His guardian, J. Carl Wilson, has filed a motion for substitution of a *693 party. Although the motion is styled as one for substitution, Wilson, who is not a lawyer, seeks leave of this court to act as Grudzinskas’s attorney and represent him on appeal. This motion is DENIED.

Although this court applies less stringent standards to parties proceeding pro se than to parties represented by counsel and liberally construes briefs of pro se litigants, pro se parties must still brief the issues and reasonably comply with the requirements of Fed. R.App. P. 28. Grant v. Cuellar, 59 F.3d 523, 524 (5th Cir. 1995). This court will not construct arguments or theories for Grudzinskas absent any coherent discussion of those issues. See Brinkmann v. Dallas County Deputy Sheriff Abner, 813 F.2d 744, 748 (5th Cir. 1987). Grudzinskas makes no coherent argument challenging the correctness of the district court’s judgment. His appeal is without arguable merit and is frivolous. See Howard v. King, 707 F.2d 215, 219-20 (5th Cir. 1983). Because the appeal is frivolous, it is DISMISSED. See 5th Cir. R. 42.2.