Chris is both victim and abuser. Chris is indeed a childish, gullible autistic adult but he's also a manipulative, abusive, entitled asshole. He didn't deserve to have someone trying to manipulate him into killing himself, but neither did Barb (as much as I have a hard time feeling sorry for her), Snyder and Megan, to name a few, deserve what he did to them. This doesn't change the fact that his life is a tragic one: his dreams will never realize themselves, in no small part due to his own feats and nature!
The one I feel the most for is Bob. He was a flawed man, but he still loved Chris dearly and tried his best, no matter how wrong his ways were. The wheels of this tragedy were put in motion way before he died, but as long as Bob lived he would act as the brakes to this train crash!
As long as Barb is part of the equation, Chris is fucked. A good deal of his worse traits, such as being a manipulative, narcissistic asshole, come from her influence. If Chris were humbler, he would probably find himself a wallflower and live a happy life. There's always going to be someone who is mean to the mentally handicapped, it takes patience to deal with them and their own peculiarities, but if Chris had a nicer, friendly personality and a better degree of self-sufficiency he would probably fare much better in life, even as the village idiot of Ruckersville!