A KO due to exhaustion was the only thing coming, we all agree he has bad cardio, he would have been KO'd by Floyd when Floyd was landing at will if it was a bad chin
I'm not a doctor and didn't study his brain after the fight so i don't know about this irrefutable brain damage but every fighter that pursues a MMA/Boxing career is leaving a piece of their brain in the cage/ring.
Straying off the topic tho, buddeh...What about his chin? Isn't that the subject you wanted to explore?
What about Floyd and Nate not dropping him or rocking him shows a bad chin?
Nate is the only guy to really hurt him, he got countered by a 1-2 he didn't see coming, Nate doesn't have to be some godly power puncher for shot he didn't see coming to stun him.