As I see it, one of two things could have occured within the story:

1) This guy is trippin' balls and none of this actually happened. I, for one, don't believe him.

2) It really happened, and he was the chosen one, but he was never meant to succeed. Forgive the horrible reference but did any of you see Space Jam? Do you remember the moment when those 5 tiny little aliens told Bugs Bunny that they were kidnapping him? Bugs told them that they had to let him and his friends defend themselves, that it was a rule. Well perhaps that is the case in this little narrative. I can see these blue-green aliens sitting around saying, "Intergalactic protocol demands that we must give these humans a chance to defend themselves before we may invade... What are we going to do? Oh, I know! We find the most wacked-out nut-job on the planet, tell him what we're gonna do, and watch him make an ass of himself. How about that guy; wow, he's really fucked up. No one will ever believe him... if he even remembers!"

A chain is only as strong as its weekest link...

That's the way I picture it in my head, anyway.