I can certainly believe it hit him in the head, maybe even dazed or knocked out.
But if a guy can survive a hit from Lenox Lewis or Mike Tyson, it's hard to imagine it being fatal.
They're fighting peers. If they hit a 12 y/o, they will kill him with one shot. Their jabs are over 300 ft-lbs. The recoil E is the same as a 460 weatherby mag->60 ft-lbs.