No, he was not informed. They were two developer accounts with two email addresses. To me it does not matter if they were linked by the same credit card. I pay apps for my family, does it make me linked and responsible for my relatives' actions? Should my app store account be deleted when they do something wrong, without contacting ME ?
He gave her test hardware and used his credit card. That's enough to link them. These are developer accounts that are, and should be, held to a higher standard than you buying apps for your family. And yes, if someone in your family used your credit card, there are lots of sites where any other account using that card would also be banned, PayPal for example.