I’d say sue the estate. Hopefully there’s none left as the proceeds have been distributed to heirs.
Why shouldn't legitimate loans be repaid? If money was paid out of an estate in error, where is the honor and personal integrity in not returning it?
Sorry debts should be paid by the estate before the heirs get a penny.
Generally speaking, and at least in the jurisdictions I’m aware of, when a person dies, leaving a will that is probated, the estate is required to publish notices for a lengthy period during which claims can be made against the estate.
After that time expires, the attorney or executor can determine the assets and liabilities, and disburse the residual funds to heirs to close out the estate.
Any creditor, especially collection agencies and credit card companies should have seen the notices and acted in a timely fashion. If they didn’t, I don’t see how they can try to collect from relatives. Not that that seems to stop them.