Well, I get the feeling he has indeed done little to no running and is not immersed in the running community. Doesn't appear to have a Strava or My Connect account. May have borrowed the GPS watch.
So likely has no idea how preposterous his performance is. So yeah, being dishonest is bad, but he probably thinks 2:46 off zero training and very odd splits, per mile and first half/second half is just kinda good run for a non-runner.....or something.....
But he claims to have won bets/challenges off of other people. That's no way to treat co-workers, relative or friends though....odd ball.