To pity, or not to pity?

I don't get "Alex" at all. Obviously, he is very unhappy, but so far the writer has not written enough about him or his past to grasp why. I'm not sure if I should feel sorry for him, or if maybe he got exactly what he was really after. Was he so ticked off at someone/everyone that he had such a strong desire to prove his complete independence? Was he clinically depressed? Was he mentally unbalanced? I can understand that someone might want to escape to a new existence if they're unhappy. I can understand someone having a sense of adventure and wanting to see places and have new life experiences. But what in the world would cause someone to go hungry unnecessarily, to sleep under a tarp in the desert instead of in a comfy bed, to live as a hobo and a hermit when there are people who care about you? Will we find out?