If you actually read what he's written its pretty obvious. He's played for 5 hours and gotten to the fifth gym and seen 200 Pokemon. In a game he's playing for the first time? Seems legit.
Wow, I didn't catch that myself. But that was because I was trying to not spoil myself in case it ended up being true. Even now after playing the games so many times, I don't think I could get to the 5th Gym in less than 10 hours, so yeah. No way that would have ended up being legit.