Hearing Aid Whistling Sound

I have an elderly couple who live next to me. They are in their eighties … Need advice.?
He wears a hearing aid and refuses to batteries because his wife is always yelling at him and giving him orders. Because of a certain type of whistle that keeps sounding the batteries weaken, he rides all day long thinking about the tea ready! Should I mind my own business or offer to buy new batteries. Their children and grandchildren do not leave the vicinity. He smiled and she did not seem to be happy about him not being able to hear … What to do? … What to do??
If what is supposed to be funny, I think he missed the boat! If you are serious then why do not you buy one year supply of batteries, and perhaps make other things good for them, they could probably use some company.
Bubbie playing her hearing aids