Curlywhirly
I always wondered why people get offended when someone suggests that their hearing is deteriorating. After all when we need glasses, we happily go along to the opticians. I myself have noticed that I now am having difficulty hearing some things, and realise that I must make an appointment to get it sorted, but I'm not the least bit offended if someone mentions it to me, why would I be? It's not something to be ashamed of!
People get offended both when their hearing loss is mentioned and if you query their eyesight, if they either have not noticed that they no longer hear or see as well as they did.
Another reason could be that they do know they no longer hear as well /see as well as formerly, but they don't want to admit it because they see these things as "old peoples' ailments" and they do not want to admit they are old.
In either case, you risk hurting or offending the other person by remarking on their apparent diminished sight or hearing, but if you do not do so, they time will come when you no longer dare accept a lift from them and you will find yourself constantly having to repeat whatever you just said.