Our 13 Year Old Son Has Been On Focalin (20

Our 13 year old son has been on Focalin (20 MG) resperidone (1mg) along with intuniv (4MG) for about a year now with a diagnosis of ADHD and tourettes. We have noticed eye movements and trouble getting to bed most nights and he insists on having a bright light on every night. He rarely sleeps through the night. We want to take him off of resperidone, and frankly, want to bring the intuniv down to 2 mg - we were told you have to wean him slowly off of intuniv - he weighs close to, if not a bit over 100 pounds.
Q: Can we take him off of resperidone - cold turkey?
Q: Can we take him down to intuniv 3 mg, next week, then 2 mg, in about two more weeks?