Apple music (on apple 4K TV) keeps asking for another users password.

Somewhere in the distant past, my son had an apple password linked to my account somehow? Not sure but that has been years ago. Still, even though his username appears nowhere in any of my accounts (not using sharing either), the apple tv asks me for his password when I power it on. Always comes up in apple music by default I guess. When I select the “not now” option, it just asks again and again. I have to select the “not now” button and then really quickly scroll to another selection (movies etc) to make it stop. It’s quite annoying and I’m really at my wits end to figure it out. I have reset my apple TV to factory settings multiple times in an attempt to remedy this issue. Nothing seems to fix it. I have all apple devices, and the apple TV is the only one that does this. Any ideas are appreciated!