I'm sure that he is a good man...just experiencing a fair amount of pain! As for him picking fights and telling you to leave I would say that you are correct in that he believes that if you do he can re-establish his relationship with his daughter. Though I would go as far as to say that when he does this he isn't thinking that....that the thought is subconscious. He says that phrase to you typically out of frustration and projection. He's projecting his anger and frustration out on you because you are the closest person to him and also that you are "safe" in that he knows that he can always come back and say that he is sorry and that all will be forgiven. One thing to note is that each one of us has a boiling point and I think he needs to be consciously aware of this notion.
One thing that he may not be recognizing is that his daughter has made this decision all on her own. She probably decided that if she withdrawls her love that he and her mother will eventually get back together and that she perceives you as a threat to that happening. Mind you I am merely speculating but that's my instinct based on years of practice. I've seen this particular behavior many times over and it only serves to bring pain to everyone involved.
I really hope that he gains the insight and understanding to go see someone as I'm certain that he is experiencing a great deal of emotional pain and I am very sorry that he is....that your whole family is.
I'm truly glad that I could help and should you need anything in the future please don't hesitate to ask for me personally. Take Care and I wish you and your family the very best!!