So meanwhile, he’s basically impossible to communicate with, but doesn’t tell people “what did you say? I couldn’t hear you”, he just acts like he heard them and then just makes up whatever he thought they said.

Man, do I hate this. My grandma does the same - she didn't want to get a hearing aid for many, many years which led to her hearing becoming absolutely terrible. She now has hearing aids, but she still doesn't understand much if you don't raise your voice a lot. Yet she acts like she understands everything, and you have to try and interpret her nods to figure out if she actually understood it.

I mean, I get why she does it, she doesn't want to annoy others by constantly asking - but I'd talk to her a lot more if she was honest with her understanding, because it's impossible to make a point more than 2-3 sentences long as it is.