I was 4 when my stutter started, and was 8 when my parents helped me with the “passive air flow” technique. It’s basically just relearning how to speak “normally”. But we as stutterers have many layers that complicate the speech mechanism. Neurological, physiological, etc. but learning those techniques at such a young age gave me a chance. Dr. Martin Schwartz had amazing insight, albeit somewhat possibly outdated by now. But many things still help. Look him up. 😃I feel your sons pain. I’m sorry you have endure this. But what a loving parent you are!