Apartment above harassing

Hi,

My Dad (62) is disabled and I just moved him into a low rent apartment on the ground floor.

The neighbors above him are playing a noise that is like a fast repeating chirp loudly all hours of the night to mess with him. He’s made police reports and notified the office but no one seems to help him. He sent me video where I clearly can hear the sound.

He does have a temper and can sound crazy when he talks, so I think everyone is writing him off.

What can he do at this point to make it stop? Or what type of revenge can we take to force it to stop?

He asked to move out and they will hold him (and I co-signed) responsible for 10 months of rent.