On pages 126 to 129 of Montana 1948, David walks to town. En route, he experiences a disturbing new train of thought. What is that train of thought? How might this represent a significant turning point in his life?

I'm not exactly sure what chapter you are meaning. David tries to suppress a series of thoughts about how Frank could want to sexually abuse Native American women when he had a wife as attractive as Gloria. David begins to change his view of his uncle and the white people who defend him.