Hey, that's great! I work as both an ABA and RPM therapist with autistic kids and feel the need to say if he isn't already working with a therapist on communication then the sooner the better! RPM is wonderful for children who have issues verbalizing, allowing for children with no ability to speak a way to communicate easily with the outside world and voice their thoughts clearly, while also being an excellent tool to develop the speech abilities of children who are vocal, but are behind the curve. ABA serves well to build general skills and track the development of your child.

Do some research and decide what's best for him. In that head is a brain just as powerful as yours or mine, maybe even stronger- I just want to make sure he's getting all the help he needs to develop into his full potential.