If he was diagnosed bipolar that is really tough. My mother and my daughter are both bipolar. My mother could never overcome the illness. My daughter I think will conquer it. She is on the right path. There are so many mentally ill people in this world. About 20%. The detaching is about the only thing you can do. Most bipolar people refuse to get help. I know my mother is that way. My D23 at least will accept it. She has taken charge of her own mental health. So I think she can stay on top of it.
Being on the other side of a bipolar person is horrible. Good luck.