Billing problem issue in apple store

why does ‘billing problem with previous purchase’ pop up whenever my brother hasn’t paid for his own subscriptions? to give some context my brother used to have an ipad but he doesn’t really use it anymore and gave it to me like a year ago, however sometimes my brother doesn’t pay for his stuff on time so whenever this happens and i need to update something it won’t let me until he’s payed it off and this has been an issue since i’ve had it, at first i thought it was because everything wasn’t synced yet but it is still happening! i’ve tried to put in my password to see what’s wrong but it pops up as wrong password even if i type in old ones but everytime i type his password in it logs me out of the apple store.. we don’t use Family share so I don’t know what the issue is