as a 19 year old girl with a stutter, i feel like i’ve gotten over being overly worried about my stutter. The last time i did speech therapy was in like 7th grade so about 5 or 6 years ago and i was glad to be over with it. going into my second year of college my stutter is the least of my worries so there’s a chance that your son feels that way to. there isn’t much you could do for him when he doesn’t seem to see it as a big enough problem to want to try to “fix”