Family Business

As I have said before, my extended family (particularly on my father's side) is rather loaded down with neurological and psychological baggage. There are heavy-duty strains of bipolar disorder, Tourette Syndrome,OCD, depression, and genetic disorders. For example, my cousin has a rare genetic disorder, Williams. It is a peculiar and interesting phenomenon because those who have it are severely affected in some ways--most have extremely low IQs, for example, but are very articulate and musical prodigies. Consequently , it is hard to get people to understand or believe that they are disabled, but they are.
Her dad, my dad's half brother, has been struggling with depression and probably OCD all his life (untreated) and in addition, has the added worry of his daughter and for many years, his mentally ill wife, who died last year after a long and terrible illness (mental and physical) that was never properly diagnosed, but was probably genetic since her own mother died under similar circumstances.
My uncle spends a lot of time out here visiting my dad, me, and my cousin in Oakland. He would like me or my cousin up north to help him overcome his depression and make a better life for himself, as I have been able to do for my parents. However, I am really not able to take on any more responsibilities. I have enough, and when I am someday done with them, I would like to take care of myself for a change.
My uncle has a son in his mid-twenties (I think that's his age). But my cousin denies that his father needs help and refuses his father's requests to move in with his son. I understand why my cousin would feel that he cannot help. He watched his mother suffer and die, and there was not a thing he could do. He probably feels the responsibility for his sister hanging over him too, and perhaps even fears he could end up like his parents, mentally ill and depressed, one day. On top of this, he just got married. So I see why he would feel unable to deal with his father right now, but he could at least help him move into a senior community, encourage him to get psychological help, help him to pack up and move out of the house. I, on the other hand, really can't do anything like that, though I have repeatedly tried to get him to see a psychiatrist, without any success.
My dad thinks that if he moves out here, everything will be okay. I doubt that, though at least he would be out of the house where his wife died, most likely by her own hand. That would help, but he wouldn't leave his daughter, and I don't believe she would come out here with him, even if he could enroll her in a program that would support her and pay her rent like the one she is in where they live. She lives with a man who is almost her father's age and whom my uncle despises, and I don't think he would come out here with her anyhow.
I hesitate to make any offers to him; I don't see how I could handle any more responsibility than I have right now, but on the other hand, can I just let him go entirely out of his mind and do nothing? A dilemma.