@terrinan - I am so sorry to read about your situation. No need to apologize - I can imagine how terribly frustrating it is.

Not sure I can offer any solution/s, but I did experience this in my father's later years, and in our family's case, I believe it was more about "selective hearing" on his part (when he'd always ask any of us, immediately, to repeat what we just said), and then he would talk in a reduced volume. He reluctantly got hearing aids in his later years, too, but it didn't improve his hearing, as far as I saw and experienced it; same for my mother, who would reply with sighs to his never being "tuned in". This may well not apply to your situation, but I sadly believe, and experienced, that it was a passive/aggressive way to control the environment around him. Nothing new in our family dynamic most of my life.

I know you're not writing about hearing, but in the interest of offering up other experiences, I wonder if physical hearing impairment plays any part in this? And not saying there is anything more in your dynamic than what you've shared, just hoping it might be of some help along the way.

It is very challenging.