sometimes, a stimulant (upper) plus a tranquilizer/neuroleptic is a good option. I have an acquaintance (not with your son's set of problems, but...still...) who found relief from a broad range of "issues" with seroquel at night and an adderall xr capsule in the morning. the downside is I think there's some indication the TD risk goes up a bit, and if one gets problems from the neuroleptic (akathisia comes to mind), then the amphetamine or Ritalin can make it worse, not better. blah.
sorry about this situation.