Who is Grandma Dowdel from A Year Down Yonder and what is their importance?

Grandma Dowdel is one of the novel's main characters. She is described as larger than life and tough as nails, living as a widow in the depression era. Her husband has been dead for many years, and she's been living on her own for a long time. Grandma is self-assured, opinionated, generous, and fiercely loyal, especially to her granddaughter, Mary Alice.