The dude used to be a bouncer, went by the nickname tugboat, (as his family says "because he was so big"), I'm thinking had pretty good experience in dealing with scuffles and brawls, as he had about 45 - 5-0 pounds on the teenager (who has no history of getting in fights) -- AND he was locked and loaded, with injuries that didn't even require a bandage, I'm gonna say...a bit more than the picture that is revealed by the evidence.
But hey, since so little of the forensics, crime scene reports and witness statements have been seen, I guess we'll know at some point with more clarity.