Answers: Call the customer service number printed on the ID card. This is the only style to know for sure.
I assume you have coverage thorough work and your son be on the policy. If your son just turned 18 (another assumption) afterwards he will remain covered as long as he is a college student. If he is not in college, afterwards his coverage may have completed. You should call the insurance company ASAP or see your HR department ASAP to confirm this. You can ring up member services, here should be an 800 number on the card to verify. Also, most companies now enjoy a website. You can register online to get coverage info and also judgment claims info.