My nephew is 19 with autism he was put on biploar medicine and anxiety medicine now he has a meltdown everyday could it be that its not the right med?

See below: It may not be the correct treatment, and certainly a side effect of those medications. He needs to be reevaluated.

On a limb: I can't give medical advice here, but i can share my experience. ( an " expert" is someone who's made all the mistakes) anti-anxiety meds called ssri's can cause agitation if not used in tiny doses & slowly increased in kids with asd's. It sounds like an adjustment in doses may be the first thing to try.