With one justice dissenting, the Illinois Appellate Court concluded that the nullity rule applied to Daniel Houlihan’s pro se petition for an order appointing him administrator of his mother’s estate.Houlihan’s mother, Carol Mattson, died in 2016, and he reportedly intends to pursue a claim against his sister for allegedly dissipating Mattson’s assets. But because Houlihan isn’t an attorney, a Cook County judge denied his petition for letters of administration, without prejudice.Affirming that …