Clearly SOMEONE has used your father's credit card number AND email address to subscribe to the Photography Plan (Photoshop). Since it's both it's possible your father chose a "free trial" two years ago, without realising that it would charge after the plan. Or someone gave a one year gift card which then switched to charging. I assume you have spoken to everyone with access to the computer. I would suggest that someone had hacked the card, but they would have used their own email address in that case. You need to tell Adobe to CANCEL the plan; however, they may refuse to talk to you as you are not the account holder. There may be a penalty, but you might be able to negotiate on that given the circumstances. If your father cannot talk to Adobe you may need to have your credit card issuer cancel the plan. (I do not speak as a staff member; this is not customer services but a public forum.
Please understand that while we all sympathize with you, this is a public forum, not Adobe support. Users, including the ACPs and MVPs, can't provide support for account, subscription, billing, download, or product activation issues. Support for those issues requires an Adobe employee.
And unfortunately, like every other company right now, Adobe has fewer people available to help and there are more people asking for help at the same time. Wait times, whether on the phone or in chat, are going to be extensive, and there's nothing anyone here can do about that, either.
I really, really hope that someone from Adobe can help you solve this issue and soon. It sounds very frustrating, and it's not as if anyone needs any more stress in their lives right now.
I appreciate this - sorry for the misuse, have now (hopefully) removed inappropriate (if, incredibly frustrated) post and I much appreciate your response. (Good to know there are people out there at least!!)