I really feel that your uncle should make the decision on whether he want to have one hearing aid or two hearing aids. It is all up to him. You can not tell him to get hearing aids if he does not want to get another one or prefer none at all.
I tried that with my mother when she lost her hearing years ago (she passed away in 2006). She refused to wear hearing aid and my sister tried to tell her that our mother need hearing aid to hear sounds, but she stubbornly refuse to. So we left her alone. That is sad but still it is all up to the individual's decision to have hearing aids or none at all.
So don't force your uncle to wear hearing aids like it is a must. Just letting you know how it goes with the person's decision at his age. 
