What should I do with children stuttering.?

Hey, so my brother is 9 (10 in Nov.) and he has a stuttering problem. He stutters on a word and has a hard time finishing the sentence. I was wondering if there is an exercise or anything he could do to reduce the stuttering. I wonder if it is because our family is bilingual. We are Vietnamese and talk Vietnamese at home. He was born in the US. Thanks for your help.