It is really imperative that you give this movie some slack ... a lot of slack actually. The things that happen here are unrealistic at best. But it is about believing in oneself. It is about never giving up. Of course there are quite a few flaws and downfalls. Not just when our main character is supposed to watch over somebody else - when he can't see a thing.
Is that something you would do? Or accept from someone else? Or make any sense in the real world? How far can someone go by not telling others that he has issues? And can we as viewers forgive him for that? It is about really really getting into the mood of the movie and accepting certain things. Especially that this is a movie, that tries to make you feel good! And it also tries to send a positive message ... even through all the wrong doings and escapades we witness ... so it' up to you: can you dig it or not?