I heard a piece on NPR on this guy a while back and then this morning I saw this article on CNN.com. I agree that the human body is capable of a lot, but just as important would be the conditioning of the human mind. It is good that he has a meaningful, strong cause that is motivating him. He did all 50 states, and actually 51 marathons (two in one day!). Oh, and he logged a PR (personal record) on the last one. Why not!
His blog his interesting and gives a more detailed version of his craziness. He ran the Iowa marathon on no sleep!