Well, this is an opinion based question so it could go either way. I think it’s difficult because like anything, s*x can be an addiction. Though there is therapy, getting someone to do the act can be cheaper & easier.
I believe the answer is: Four years
During the renewal process, the disabled drivers would receive a temporary paper that can be used in case the police ask for it before its done. If the drivers are caught with expired license, they would be subjected to traffic citation or some amount of fines.
Talk to him and see what the problem is and if they still don’t improve fire them