For background, I'm a high school senior guy, XC captain, and state contender. Our team has been more cohesive than ever this year, aside from one outlier: our #8 guy (19:22 5k) has been getting uppity at practice. He races everything, including warmups, tempos, long runs, and everything in between. He's also incredibly condescending: The girls captain had to miss one day of practice to go to a funeral last week, and the day after she got back she accidentally called out the wrong drill during our warmup. She immediately corrected herself, but not before good ol' #8 could say 'Maybe you'd remeber if you were at practice more often. Real captains never miss practice.' I'm pretty sure I would've killed him if our coach hadn't been nearby.
That's just one example, but he does stuff like that every day and everyone on the team is getting fed up with it. What should I do about him?