Don't worry about the breaking balls, concentrate on the FB and change up. Regardless of the argument whether it causes injuries, young pitchers need to learn to rely on their FB and work on location above all of their other pitches, no matter what their velocity is.
My take is that most young pitchers who have success with breaking balls tend not to use their FB due to fear of getting hit. JD is correct, they become so infatuated with it, they use it too much. I could have seen this happening to my son when he was younger, instead he was "forced" to rely on his FB and change up and not actually relying on the actual CB or slider until college. Finding a coach that allows a young pitcher the opportunity to learn to use all of his pitches is a good coach, IMO.
I haven't seen one college or milb pitcher who ever relied soley game after game on breaking balls, the whole idea is to keep them off balance using a variety of your arsenal. Yes, I have seen many coaches call breaking ball after breaking ball, but eventually the better hitters adjust.