sadness anger and what else...

My uncle who is 64 years old and has had so many health probelms is smoking again. I dont even know if i can say he ever even stoped. He had tripple bi-pass allready and many other operations but his health has been very poor. He is killing himself. His depression is bad, really bad. He is upset about nonna all the time. He talks about bringing her home sometimes. He is trying to drag us down with him. I cant take it. I used to look up to him, but now whenever i think about him i just want to throw a punch. I dont know how to handle it anymore because he DEFINALY does not respect me. To him I am a child nothing more. I dont hardly matter in his life so how can i go about talking to him about this stuff?