A man with a ‘hearing aid’ can communicate easily, but cannot enjoy the fun of music. Why does the person clearly understand the human voice but not the music?
Is this a general question, or about one specific person?
What's the nature of his hearing impairment? Maybe he only hears a limited range of frequencies. Or maybe the aid is designed to only boost a narrow range. Speech intelligibility is between about 1.5kHz and 4kHz. Anything outside that range might be deliberately filtered out. Try him without the aid but with music headphones. Does he hear the music now?
Hearing aids are designed with the priority of being small, light-weight, invisible... A relatively cheap set of music headphones, without those restrictions, might do the job a lot better. It's worth a try, anyway!