I want an Apple account the family can use.
The account must have a card.
I attach my card to the account and the users have access to make purchases.
Unless Apple allows the account to restrict which users have access to make purchases, I would opine that dad has allowed each user on his account to use his access device he put on the account. That is, he can say hot card my account and nothing gets paid, or pay the incoming charges because I have authorized these directly or indirectly.
The bank cannot differentiate which charges were from which users. Dad needs to secure his card (info) if he doesn't want the Apple authorized users to be able to use his card. Then Apple gets upset, but hey, at least dad will have his money.
My opinions are not necessarily my employers.
Rules and Regs minus Relationships equals Resentment and Rebellion. John Maxwell