Fil Put 17k On Old Joint Card

My father in law has gotten involved in many scams. We just found out he gave away the majority of his retirement savings to someone online through bitcoin and gift cards. He was reported by my BIL to a social worker who showed up to talk to him. The social worker will not give us any information for privacy reasons.

In the same day we found out he put 17K on a credit card that he shares jointly with my husband. We are guessing the charges are time share payments and money for scams. Unfortunately this is a 20+ year old card that my husband does not use and had forgotten about. At first my FIL said he would make it right and get a loan to close the card but of course he cannot bc he has no money or credit.

We asked him to debt consolidate, sell his things, etc but he doesn’t seem to care to make it right. I am afraid he may default and we will be responsible. Do we have any legal recourse at all? Can this be reported anywhere?

We do, unfortunately, own a house together. He lives in an in-law sweet and is on the deed but not mortgage. He had put money down on the house and now says he somehow wants to use this to pay us back, which makes no sense. Not sure if this is relevant but I’d be happy to give details if needed. He is not being logical am I am unsure if some of this is related to his deteriorating mental health. Clearly living together was a huge mistake.