I've suffered torn rotator cuff. It hurts and is pretty disabling to the arm and shoulder in question. On the other hand, I'm not a professional boxer...Not near his size either, but I'm not sure that matters much.
Cool. I have only had severe ankle and head injuries, but nothing shoulder. Should he have boxed one armed for a couple more rounds? Maybe. But I disagree on the size part. What would be painful to you, considering you aren't bohemoth Vitali size, would be even more painful for him because he has to lift higher and such. Like lifting, it is harder for a longer limb person to bench than a shorter version. That would translate to doing activities with a hurt shoulder.