You can't blame him for being down syndrome and living at home/being a bit crazy, but i understand, all you can do is hate the reason and if he is it, who am i to tell you otherwise.
I do not pray as i don't believe 'he' helps us i believe we help ourselves. I believe your love for your aunt will serve you and her well.
"While you're waitin' and feelin' alone
Nobody knows why your love is all we need to hold on"