Does this person have any joint accounts with the ex? Those would be protected from creditor contact with the co debtor stay while in a chapter 13 but after discharge, all debt that was joint will fall on the other party. In a chapter 13, payments are made on the debt and unless it is secured, it isn't always at 100 percent . Depends on lots of factors etc (secured is paid at 100 percent in chapter 13) so if had unsecured joint then that is where the problem would arise.