What is wrong with my father ? He is out of touch with reality ....and he thinks I am his therapist?

My dad thinks he this chosen One like a Buddha or a Jesus or something. He thinks that people know about him and he is famous and only certain people know of him and they follow him (he's paranoid ) He believes they (these people) do things out in public to show him he's not important. Then he becomes angry and depressed that they are screwing with his head . For example if someone does not hold the door for him he says it's them screwing with his head to try to show him they don't care about his gift . He thinks he can go into these enlightened states and effect everyone in the room . He thinks the song ONE and WIDE AWAKE by U2 are about him . He complains to me about it constantly and asks for my opinion but if I dare tell him that he's wrong and mistaken he becomes angry and flips out crying and throwing a fit like a two year old because I don't believe in his powers. Then he will spend hours trying to convince me that he is rite and try to make me feel guilty for not believing in him he just won't let it go he won't let you disagree with him he will harp you and corner you until you just agree to shut him the hell up . He has been put in the hospital before when he goes into one of his rages and flips out but he lies to all of the therapists so they let him out. He would never dare talk to them like he does to me because they would think he's crazy....guess what he is crazy. I am sick and tired of listening to him complain about these delusions he's obsessed and I'm fed up with biting my tongue just to avoid a fight. How do I deal with him ? Have you ever has to deal with something like this ? I try to talk about something else but he always comes back to this subject. If i allow him to talk he thinks I agree and won't shut up. And if I tell him I think he is mistaken then he throws a fit and becomes depressed then again wont shut up trying to convince me he's rite. I feel like a prisoner to his nonsense I have had it he has been believing in this crap for 30 years he even convinced me of it when I was younger.