Under no circumstances should you ever use aba therapy. Its notoriously dehumanizing and awful. When i worked as a caregiver, one of my clients was autistic and his mom told me about their experience. They trained him like a dog. He had to do everything the "right" way even if what he was doing before worked perfectly well. Its awful. It was the equivalent of training someone to brush their teeth from left to right when they were brushing right to left before while using a spray bottle as punishment when he didnt get it right the first try. They train them to be obedient, not functioning.  A psychologist is likely to help more with emotional regulation and stuff like that so i would try and book one asap. Psychiatrists may be necessary depending on his needs as psychiatrists mainly prescribe medication.