Shawn McDonald insisted his brother John W. McDonald III’s marriage to Ellizzette McDonald was void because (1) a few weeks earlier a Kane County judge had appointed Shawn as plenary guardian of John’s person and estate based on a physician’s report that said John suffered from “bipolar disorder with manic and depressive episodes” and a “severe” level of “alcohol use disorder” (2) Shawn wasn’t notified before the wedding ceremony (3) there was no judicial determination, under Section 11a-17 of the Probate Act, that the …