How does the characterization of the grandmother contribute to the meaning of the text as a whole?

Grandmother is a cranky old woman who lives with her son, Bailey, and his wife and two children. She is preoccupied with appearances and snobby about "common people." The cynicism of the world really comes out through the character of Grandmother. Despite her Christian faith, she sees no redemption in man. The Grandmother states that, "It isn't a soul in this green world of God's that you can trust."