Legal Question in Credit and Debt Law in Pennsylvania

Unless your mother signed personally for the cards or used the cards, she should not generally be liable for your father's credit card debts. However, it depends on the assets in the estate and where your father lived at the time of his death. I recommend that your mother take your father's will, if any, to a probate lawyer who can then review what assets are in the estate and make sure that your mother gets her spousal allowance (called different things in different states) which is free of creditors' claims. If there are no assets in the probate estate or if the probate estate is exhausted by the spousal claim, then there may be no need to probate an estate. In which case, I would tell the creditors that your father is deceased, that there are no assets and an estate will not be opened.

If there are assets which would pass through probate, then your mother may have to pay the bills, but out of estate assets, not her personal assets. Basically, heirs cannot keep the assets and not pay valid debts.