I had the same question re. the busted stablizer. Even if the bow was dropped, I doubt if the stab would bust. That's a real headscratcher.

Re. dry fires, I've been pre-occupied/absent-minded enough to do it four times in the last decade: twice on a 50# Hoyt Accutec, once on a 60# Darton Cyclone LD, and once on a 55# Mathews Feathermax. None were the worse for wear, but maybe I was just lucky, so you should still get the bow checked out (and make your bro pay for it!).

I still have the Hoyt (with at least 10,000 additional shots on it) and the Darton (with at least 4,000 additional shots).