Did Jess Willard kill someone?

Two doctors disagreed on what caused his death, one said it was Willard's punch to the jaw, the other said it was Young's head hitting the ring floor very hard when he fell.

 

I'm not a doctor, but if l had to guess, l would say a 6'+ guy falling hard on his head without breaking his fall is probably go to do more damage than a punch.

 

From the accounts of the fight, Young was caught by an uppercut while rushing in and just sort of crumpled to the canvas vertically. It doesn't sound as if he fell heavily enough to injure himself.