If it was dislocated (sostochondral separation), I've popped a rib out twice - not close to the most painful injury IME, barely hurt after just popping it back in by moving around a bit (back to working in a kitchen the next day the first time, but it took quite a while to not feel like it was gonna pop out again, still a sore connection a couple years after the last dislocation), but it was freaky to see a few inches of rib protruding, especially the first time around. Maybe it can be more painful tho, plus my pain tolerance is high if there's no blood (since I was a kid things ppl make a big deal about aren't so painful...useful sometimes, but only if you also learn to listen to pain, to avoid injury).
It would've compromised all his movement - grappling, clinches, punches, breathing whatever. Even worse for a wild style like his. Plus fighting would damage the cartilage more and make the recovery harder. No way it's worth fighting with it.