The only Medicare that might cover hearing aids is Medicare C, aka Medicare Advantage. There are pros and cons to this type of Medicare, so a user should research the long term implications thoroughly before deciding.
My group health plan while working actually did cover hearing aids, and quite generously. So I got them about 6 months before retiring. Glad I did.
All this talk about "not needing" to hear higher frequencies is nonsense, btw. Every instrument's tones contain overtones that go up,up, up. Not hearing those gives you a dulled sense of the instruments true sound.
I know that my life would be significantly less pleasurable if I could not hear the fullest possible range of cymbal overtones, or the higher overtones made by a vibrating reed, or...on and on.