Credit card troubles with the MIL 😡

Before my husband and I met and he was still being controlled by his mother she took out a credit card in both their names without his permission. She gave him a card of his own but told him he was not allowed to use it without asking her and he would have to pay her back everything he spent. We’ve now been married for a year and are trying to build a life together. We noticed his credit score keeps dropping so we did some looking. She still has the card and has maxed out the limit of $1250 and isn’t making payments which is killing my husbands credit score. So my question is can my husband call the credit card company and have himself removed from the account or the card canceled since he’s a secondary card holder and she opened the account without his knowledge?