Is co-signer also responsible for insurance?

Dear Terry,
My mother-in-law is the co-signer on her son's car loan and he is on her car insurance. He hasn't paid her for his car insurance, but she pays it each month anyway. She feels that since she is the co-signer on the car loan that she has to make sure the car has insurance on it. Is she responsible for carrying car insurance since she is the co-signer? Or can she take him off of her insurance and not get in trouble if he gets pulled over without coverage on the car? 
-- Shannon

Dear Shannon,
Your mother-in-law is right to worry. As a co-signer on her son's car loan she is just as responsible for the vehicle as he is.

If the insurance lapses, the insurance company will notify the loan company and the loan company will likely purchase a comprehensive policy on its own to cover its interests -- usually at an absurdly high rate -- and tack the cost on to the loan. Or it could declare the loan in default and repossess the vehicle. Your mother-in-law needs to kick her son's butt and get him to honor their deal.