I have stuttered my whole life and my parents would always tell me to slow down, which sometimes would make me more frustrated because I knew I had to slow down but still had trouble. The best advice I have is to have him start reading out loud, by himself and also with someone in the room. (usually is a big difference to have someone listening rather than by yourself) Over the years I have learned that the hand movements and facial tweaks might help you get the words out (band-aid) but creates a habit that is harder to adjust as you get older. I have heard that stuttering can be inherited, I have noticed my 3 year old starting to have some trouble but I hope it doesn't develop into a stutter. I am still learning more and more on stuttering but just recently I have learned it is also largely related to anxiety and your vocal chord muscles tensing up. I still research on the daily to better my stutter, I really hope the best for you. Also just like seeing a therapist, it doesn't hurt to try multiple speech therapists to find one that works well with your son. If you have any questions at all feel free to ask, people don't always realize how much stuttering affects someones life.