Son on Abilify (aripiprazole) 1mg since Jan 2015. Was just changed to generic by insurance. Could this destabilize him? He's not been stable long.

Generics. should work just as well as brand name. By law they have to be at least 85% as effectuve as brand name.
It could. If you notice problems with the change his doctor can order the abilify (aripiprazole) to distributed as the brand name. Most people do just fine on the generic, though we have very limited data on that for abilify (aripiprazole) as the generic is new. Just watch carefully and you could change back before real trouble occured-don't worry.