How does the book overcome adversity, difficult situations and general injustice?

I think this is more a character question about Junior more than the plot.Junior's sense of humor and witty sarcasm help Junior to cope throughout the story. As Junior faces bullying and alienation both on the rez and at Reardan, he always has the choice of letting his misery defeat him or trying to overcome it. His survival tactic, however, is to use humor to offset life's most difficult challenges. Junior often describes his tormentors in a sarcastic and flippant tone; when the Wellpinit supporters turn their backs on Junior and the Reardan team, Junior comments, "If these dang Indians had been this organized when I went to school here, maybe I would have had more reasons to stay" (144) and starts laughing. He also draws comics to display his struggles in a humorous manner, poking fun at the fact that he rarely has a way to get to school and can't figure out how to answer the question, "are you poor?" This tone makes Absolutely True Diary a story of triumph rather than tragedy, showing that Junior's inner strength helps to lift him up even when he is forced to grapple with one devastating loss after another.