Moon Shadow's dream at the beginning of Dragonwings is to meet his father and have a more coherent family. His parents live on different continents, and Moon Shadow has never met his dad. As explore in the discussion of "Friendship," however, the lines between family and friends get happily blurred in Moon Shadow's life. The book asks us, what is the difference between family and friends? And really, does there need to be a difference? Is it possible to find or make a family?
Moon Shadow does not consider the Whitlaws his family because they are demons and thus too different from him.
Moon Shadow considers the Whitlaws his family because of they selflessly act for each other's benefit.