Depends on if the hearing loss is in narrow bands or completely across the audio spectrum. I have a hard time hearing the tv, wife always telling me to turn it down.
Got a set of good stereo speakers and an amplifier at the thrift store. The kind with real speakers, a 10 wolfer, 4 inch midrange and a tweeter. Now I can hear the TV just fine, and half the time she says turn it up.
The surround sound speakers dont work, the low end is poor. What has happened is the full audio spectrum is present clearly and I can get enough clues to hear the conversations fine. With the tiny surround speakers, they primarily produce sound in the spectrum that I cannot hear well. (audio speaking range.)
Here is a general test, do you have to yell to speak to him, or can he seem to hear normally in conversations. If he can speak and hear normally when talking in a room with you, you might just get away with a good speaker system.
Focus on stereo amplifier, not 5.1 or 7.1. And get one with headphone out with volume control.
He can hear okay on the telephone and he can hear okay if you’re talking normally and you’re only a few feet away from him (as long as there’s no ambient noise). Across the room, no.
But he’ll have the TV volume at maybe a 20+ level when most people could hear it just fine at around 10.