Have you tried sensory integration therapy instead of ABA? You're saying your son has sensory issues--ABA is a teaching method, not a therapy for sensory sensitivity. I suppose there is some learning involved in dealing with hypersensitivity, but most of it is learning what annoys you most, how to stay away from it, and how to deal with the overload when it happens. ABA, as a very concrete sort of teaching style, is more suited to concrete skills that can be taught by imitation. An OT trained in teaching children how to live with sensory hypersensitivity might do more good than a traditional ABA therapist, especially if the ABA therapist is used to trying to change a child's behavior without first finding the function that behavior serves, and deciding whether it is worth changing in the first place.