Im gonna say he's hacking.It wasn't the fact that he was geting alot of kills,but the fact that as soon as he pops around the corner he instantly turns twords an enemy.For example,when he was heading out of the palace looking building (I dunno what it's called) he instantly turns and takes out an enemy on the stairs.Im not calling it a definate because like previously stated,he might have high sensetivity.But as far as I can see he is probably aimbotting.