Sven,
I worked for the New Orleans version of your old coot when I was younger.
The day I stood up, told him to STFU and get his whiny butt out of the way and let me fix what needed fixing and ditch the idiot whiny crap that he wanted to be an idiot and whine about, the other three people that worked for him (and we were not allowed to speak) almost stroked out.
I made out a limited power-of-attorney that gave me the ability to handle his banking problems, and to talk with his lawyer about other problems (he was Mr. Sue You For Anything) and told him to sign it or face the reality of nobody doing anything he wanted done.
He kept screaming at me to quit, just quit the job, and I told him he’d have to fire me. All it took was calling his bluff. He calmed down, and no, I wasn’t a research assistant, I was an administrative assistant (made him change the job description filed with his lawyer) and I actually got the mess under control enough that when he died 7 months later, the lawyer and accountant were able to handle the estate.
He told his lawyer that I was emotionally abusive to him, but efficient. The lawyer said that the old fool was such an abusive person, he’d never known what it was like, until someone turned it around on him.
Had you not already quit, i’d suggest trying it. What would be the worst he could do? Fire you?
DD