Will I be responsible as a co-signer on my son's car for paying a judgement as a result of an auto accident when he had no insurance coverage?

There was a 3 day lapse in insurance when my son had an accident purely his fault. He was sued but is unable to pay because he lost his job. I received a letter from the motor vehicle department saying that my license would be suspended this month and I had to turn the tags in on my car and his because the lawsuit was not being paid. Can that really happen even though I was not driving that car. Also can the insurance company eventually come after me for payment?