^^ LOL, good call. He's just a skinny dude, that's all.
He might have great advice for people looking to slim down. But bodybuilding (which I define as the meticulous control over the details of your body)? No.
That said, his video has some decent ab exercises for beginners. Some of them, I wouldn't recommend (like, I think planks are overrated, and he's got like a million plank variations). But any of the crunching movements are fine, particularly for those whose abs are not strong enough for crunch movements using resistance. And provided, of course, that you feel your abs contracting. If you don't, drop the exercise, and try one of the other ones.