It sounds to me that the school doesn’t want to follow your grandson’s doctor’s instructions. The don’t know if he took the medication before going to school. They assumed he was late and didn’t take medication. It also sounds like the principal instigated an altercation to have your grandson dismissed. Contact the Bar Association. They will put you in touch with an attorney who is skilled in this matter. Then throw a legal threat their way. They will leave your grandson alone to work and study. I had to threaten everyone with an attorney for my son Brian. It’s extra work in the beginning but you’ll be glad you did.