We would need to review his insurance policy to be able to provide an accurate answer. Also, before settling with the at fault driver insurance company, I would want to make sure the at fault driver did not have any other insurance or significant assets or significant income possibilities from a job, inheritance other source. Does your son have any children???? I would not sign any papers without an attorney reviewing them on your son's behalf.
Best regards,
Allen M. Wolf
TheWolfLawFirm.com
888-WOLF-LAW