You might be out of luck. The creditor's know that your name is on the mortgage and you are legally bound to repay it. It is no different then co-signing a loan for a friend for a car and then have them not make the payments.
In hind sight, you should have refinanced the house out of your name 5 years ago. At this point, you just have to make the best of it. if anything, take him to small claims court to try and get some money out of him.
sorry this had to happen to you

