You won’t find out till he is older. When I was younger, I developed a stutter, but it went away. I remember it came back like a year later, but it again went away. I feel like it happened a third time, but I am unsure. But what I do know is when I turned 12 the stuttering was full on and didn’t go away and now I have to live with this bs the rest of my life. Please don’t laugh at him when he stutters. It’s discouraging. Sure it might seem cute to some but it’s a real drag when you’re the one to deal with it. Just listen to whatever he has to say and help if he asks. It may or may not go away, it may be permanent, who knows