Welcome to the forum. Glad you found us, but sorry you need to be here!
I severed ties with my entire immediate family couple decades ago and have never regretted it. I've been an orphan all alone in the world for all my life for all practical purposes even though I have a mother and all three siblings still living, and I was already 35 when my father died. Useless, every single one of them.
I don't concern myself with what happens to them. Of course they're all going to die someday, we all are, but they're no more than strangers to me at this point. I don't think I could even pick them out of a crowd at this point, and my own mother can't remember my birthday, so apparently I'm no great loss to her either. And frankly I feel less alone in the world now than I did when I was still trying to be part of the family.
You can stop talking to your father without making it be forever, if you're afraid of not being around when he dies. Your father's not going to change at this point. He's a very sick man, and his disease leads him to verbally abuse you and to be unable to have a normal relationship with you. You don't have to allow that to happen but the only way to take control of that is to disconnect from him. If he dies alone with no contact from his daughter ... well, he doesn't seem to value you very much, does he? How much is it going to hurt him, really? I wouldn't feel guilty about something he brought on himself. You have to defend yourself from him, no one else is going to do it for you, especially not him.
It's sad, but bad things happen, and we have to deal with it. Going no contact is a reasonable response in this situation. It doesn't have to be forever, you know.