How do you make a parent who is controlling, narcissistic, (to put all this mildy) understand that you are there to help him?

Based on everything you've said here on this thread, I'd say move out. Right away. You're not going to fix something that's been broken for THIS long, so why try? I'd say to try and line up some care givers for your father before you move out, but I'm sure he wouldn't allow them to 'help' him in any way, so what's the point?

Unfortunately, you can't save a person from himself. You CAN, however, save YOURSELF. Now is the time to do so.

Best of luck!

He is like my mother, a must miss. Why punish yourself, he will not stop abusing you,move out and go about the business of living your life. He will figure out how to care for himself, those type of people always do.

God, I hate that crap. Yes, I've had that prob with autistic nephew, years ago. (I mean, the distrust & anger & freaky blowups). I'll bet its extreme anxiety cuz it sounds like he's easily overwhelmed by little things. (Please please get him some xanex, cuz I doubt that he means to be a jackass...just freaks out like that, but doesn't know he has an actual problem. Honestly, give him the med first thing in the morning, (cuz it will take the edge off), & likely will be more reasonable to talk with. I mean, those are important issues you have to discuss 4sure.
P.S. Just start with a very small dose, cuz elderly process drugs differently. Best wishes to you.👍

Is he changed from the person he once was, so that we can say "it's the disease talking", one of our favorites? Or has he been this way. If the latter is the case then understand that we are down to the choices YOU are making for YOURSELF in staying with him. He should likely go into care, and you off to job or family and a good life for yourself. He is unlikely to change for the better over the next decade and one half.