Thanks for that advice.
This is only a short term solution when he is visiting us which would only be a week or two every year with perhaps 2-3 hours per day watching TV-maybe not even every day. He only watches TV at night. He reads during the day.
I wouldn’t think in those conditions, there would be harm if he were careful.
Well, yeah -- of course not. But in the long term, it is probably going to get worse -- I suppose it might be slowed by better supplemental amplification that takes his auditory profile into account -- but aging brings worsening. Still, he ought to take the time to obtain a "free" examination if he has access to one.
This is not an expert's advice, it is advice from a layman for him to see a recommended expert.