though i a pediatric dentist
, yet i think i can be of help. we have an autistic son and have done our research on it and various drugs, every therapry has its pros and cons. i advise u to help him develop his weak areas like congnition and speech with carious activities, the widely being used is positive reinforcement therapy and sizdon is a drug resperidone it is used to decrease features such a self play and decrease his sensory issues thus giving him more responsive to the real. but do keep a check on his liver
function by regular LFT tests.