According to the South Carolina Department of Motor Vehicles a form S-22 insurance certificate is required for 3 years from the ending date of the suspension for which it is required. The SR-22 is also required during the six months when an individual is issued a provisional driver's license.
The SR-22 certificate must be on file at the SC DMV before the license can be reinstated or a provisional license issued. The SC DMV notes that SR-22 insurance is not required if the 3 year requirement period for the original suspension has ended.
The SC driver's manual states that some suspensions require SC drivers to file SR-22 insurance before their driving privileges can be restored. SR-22 insurance is proof of financial responsibility for the future. If you are required to file SR-22 insurance and you fail to maintain that coverage, your driving and/or registration privileges will be suspended and you may be required to pay up to $400 in reinstatement fees.
You will need to contact the SC DMV to get information on the exact laws surrounding your son's loss of license due to getting too many points and the reason he needs to acquire the SR-22.