Suggest Treatment For Rebellious Disobedient Behavior When Treating Down Syndrome And Autism

I have a 17 year old son with downsyndrome/austism. he is currently taking strettara 25mg & GABA a natural supplement. There has been significant changes in our life of late, relocating to new home school & support staff changing 5 times in 1 year at school. My son has had 4 violent episodes since age 14, one at 14 while on 60mg of strettarra two at 16 on 100mg of strettara and one a week ago. the latest was very violent. My son is quite heavy & I amm concerned about weight gain with antiphyscotics(family history of diabeties) He has been on concerta from age 6 to 13. this worked but basically made him into a zombie & he did not sleep & was continually taking off on us, climbing out of windows (20) feet. Taking keys & driving our vehicles etc. I am a t a loss what medication would you suggest?