Apple Music on Google Pixel Account Issues

We have been trying to set up an apple ID for my son to log in to our Apple music Family Subscription (not family sharing). We are able to create the ID, have him added, and it will work for a few days (able to download and play music, etc). Then, it logs him out and his account gets locked. When I request to have access to it, it is denied but nobody can tell me why. We tried the entire process again with a different email address (and domain) with the same luck. We have also tried to log in to his accounts on different devices with the same success. Any ideas? Customer Service literally says they have no idea and no way to find out why his account(s) were locked and why access is denied.

My husband and my accounts work just fine (also Pixel users).

Any ideas? So frustrating.