that's scary stuff. I screwed up my left shoulder a few years ago, and after I thought that it had sufficiently healed, I started benching again. Well, I did about 6 reps, and then my left arm just went out as I was trying to hoist #7. Luckily, the bar was only a few inches off my chest at the time, and I was able to shove the bar off with my right arm. I was scared shitless, though.
Hope the kid's OK