I was and am a hard head. He needs to want to get rid of his stutter. How to do that? I have no idea. Some people say read out loud. Other say go to speech therapy. Many say sing. The truth is that what I’ve found out, personally, looking at the past the times when I was most fluent was when I was around good people and I wasn’t thinking about my stutter, the wall that blocks speech was lifted by the good feeling chemicals and focus cause I was having a good time. Maybe that is the answer. I have no clue. I just payed more attention to how I and why I stuttered and just tried harder next time. You know him better than most. Sure you could figure it out. End of point is he needs to want to not stutter.