Try getting him to speak in 2-3 words block by: Lesley
My kid stuttered too when he was about 7 years old. He is now 10 and seems to have overcome his stuttering problem. He would say something like "i ...i...i....want.......to...to.... ". I was told to be patience with him and wait for him to finish his sentences. Try not to rush him or help him to complete his sentences.
I then tried to teach him to use two-three words blocks so that he can speak in byte size to complete a longer sentence. It goes something like "i want...to eat...ice cream...may i...have it....". This creates a starting point.
After some time, i would asked him to use three words block. so this time "I want to....eat ice cream ....may i have....some?". This progressed slowly and helped him gain confidence to use longer words "block" which ultimately resolved his stuttering.
Now, i am not 100% sure if this is clinically proven but it did worked for my son. Maybe you can try. Hope it will be useful to you.