G.T.
If the doc has released him to drive legally I doubt there is anything you can do.
You can go to court and change things but you must have proof enough that would sway the judge to make the changes. You cant just go in and say what you've said here. You have to prove that your child would be in danger. Lots of people drive on prescription medication every day, he would have to be what they would consider "intoxicated" by his meds in order for them to limit his driving privileges. If you have documentation of his accidents and if it is because of his injury or meds you will need to give that to the judge. Otherwise you most likely dont have a case.