Help is needed with a man suffering from Post Traumatic Stress Syndrome.?

My great uncle who is in his late 50s, early 60s, just came to my gramma's (in her late 70's, he's her youngest brother, being very similar age to my mother) house after being homeless for about a month. He's about $700 in the hole (growing still, because of overdraft fees). He was in the VA, and supposedly in a place where he couldn't get out... but he did... he does not like to stay in one area, or any specific shelter, and suffers from several health issues... he cannot walk very easily, he claims to have had a stroke, he has PTSS from his time as a marine in Vietnam, among other physical/mental issues... now my gramma would be able to care for him somewhat easily, if not for my grampa who has Alzheimer's... Where can my gramma take my uncle that he WON'T be able to get out of or be discharged from...?