Legal Question in Credit and Debt Law in Massachusetts

you can sue him or make the payments.

This is a very common problem, and people should think twice before co-signing a loan. A written agreement between co-signers can help in the event that one co-signer defaults on his or her obligations.

You can ask the other co-signer to refinance the car loan. The co-owner would probably need a new co-signer in order to do this. When you co-signed, you promised to make payments. In order to protect your own credit, I would get a promissory note from the other co-signer and then pay off the debt. That would release you from any further obligation.