I don't see this question as offensive or ignorant at all. I can't speak to speech therapy as an adult but I went through it from 1st through 12th grade in school, 20 years ago. It did help for basic techniques to help get past different types of repetitions and blocks, but did not completely make me fluent. In fact I was discharged from therapy with a statement saying that I've gone as far as I can with therapy and any further progress will happen naturally. If the option is there, it wouldn't hurt for him to give it a shot with the understanding that there is no magic bullet solution, but if you take it from the standpoint of an educational experience to learn techniques to help then it can be helpful.