It took 2 1/2 years to find what meds work for ME. We all respond differently. I will say that these drugs we take are a danger in themselves. You need to discuss the dangers with your son's neuro. It's a long hard journey and I wish you and your son the best. One piece of advice go into all your sons Dr. appts if he agrees. Four ears are way better than two. I know as a patient I don't hear or understand half of what the Drs say.
Best to you and feel free to ask any questions you have. These are the greatest. I promise you that you will get an answer.
Mike
Get copies of all tests, bloodwork ect.