In chapter 11 of Drangonwings, what give Moonshadow hope and something to believe in?

In Chapter 11 of Dragonwings, the most important event that gives Moon Shadow hope is the delivery of his mother's letter which recognizes him as a dragon. The chapter is entitled Exile and emphasizes the loneliness of Moon Shadow after leaving the Tang. But when he gets this letter and adapts to his new home, he achieves making Dragonwings.