Hi
This is from an article in the Independent from a few months ago. The answer is yes they can, as the home was a joint asset.
"The Citizens Advice charity reported last week that the number of "charging orders" being taken out by credit-card, personal-loan and hire-purchase providers had surged.
A charging order is a county court order which secures a consumer credit debt against a property, converting it from an unsecured debt into a secured one. "When you have a charge on your property, it becomes a different status of debt. There is more at stake," says Beccy Boden Wilks, a spokeswoman for the charity National Debtline. Because the loan, no matter what its size, is now secured against your property, failure to repay it could potentially result in the loss of your home. However, "just because someone has applied for one or is threatening to get a charging order doesn't immediately mean you are going to lose your house," she says. "There is a legal process to go through.""
What I would suggest that you do. Write a letter on behalf of your dad (get him to sign it), to the credit card companies head office addressed to the Chief Executive Officer. Explain the circumstances and enclose a copy of your mums death certificate. Ask them to review the account and to look into this further. In particular the charges and suspicious visitors. The company concerned should waive any charges from a certain date and look into any suspicious entries. While the credit card company are looking into the matter, they should stop the debt collection company from taking any further action. It is possible that the debt has not been sold on yet as debt companies often just chase on behalf of the creditor who is owed the money. Even if the account has been sold on, the credit card company should still look into this.
Huckster