I just tried a new search term which might describe what I was thinking about initially: "hearing-assist headphones" and got a lot of hits on Amazon as well as a few articles.I think my wife and I are in the same situation with her 98 year old mom having hearing problems....
Many are probably pretty naff and none will likely have the precision/adjustability of real HAs, but might be a help for "really senior" folks (?) esp. those with dexterity issues, depending on the amount of amplification required. One article mentioned a product from BeHear which has quite a bit of amplification.