Any advice for my cousin?

Any advice for my cousin? Hi, i'm not here for the sake of me, but for my cousin who's 17 now and has been stuttering his whole life. But since he started high-school i feel like its gotten a bit worse. Does anyone have any advice on how to help him and possibly how to do it anonymously? I know it's a gentle subject for him and i think he would feel prouder of himself if he fought it off on his own.