I have taken Strattera and my son has taken both Strattera and Intuniv but not at the same time. Typically they prescribe one or the other.
We had a lot of success pairing one of the meds with a stimulant. These meds are known to help with the side effects of stimulant meds.Maybe that is something he can try with a low does short acting stimulant. Might be worth a shot and at this point he wouldn’t have anything to loose.