My daughter inherited stuttering from me, I knew she stuttered since she first started talking in both English and Mandarin at about 3yrs. We are very mild, I opted not to do anything about her speech. For me, free speech therapy in schools for nearly 10 years didn't work me, since I am very mild and rarely used the techniques. Anyways, I never put her in speech therapy and I never brought attention to her speech. She knows that she and I both stutter though since we talked about it. Even today, my wife doesn't even know she stutters, that's how mild. She is now a typical grumpy teenager in high school. Here is my suggestion, monitor his speech. Don't shame or try to correct him talking. Things like telling him to "repeat it again without stuttering" "talk slower" "think before you talk" these phrase will make him hyper aware of his stutter. I never said any of those to my daughter. I remember my family trying to be helpful and telling me all sorts of stuff. I never brought extra attention to her stuttering. Be patient with him, especially if his stutter gets more severe, give him the time and space to talk. Speech therapy or no... looking back, if my daughter have a more severe stutter, I might have put her into speech therapy or if I noticed it affect her life more or needed fluency shaping techniques. However, the caveat is that you will bring attention to his stutterer. Consult with a professional Speech Therapist. However you need to find a good one, not sure how. Good luck!