How does Steinbeck foreshadow the unraveling of the Joad's California dream?

The various members of the Joad family become more tense and irritable as the journey continues. Rose of Sharon and Connie begin to feel a sense of claustrophobia, bothered by the lack of privacy, while Uncle John worries irrationally that he may be the cause of the family's troubles. Uncle John, like Sairy Wilson, wishes to use Casy as a preacher, a designation he loathes but nevertheless accepts. Casy's protestations that he is not a preacher and does not believe in god seem excessive. He refuses to be called a preacher because he has doubts, and others approach him as a preacher expecting certainty.

The death of Granma Joad is significant for it demonstrates just how much Ma Joad can bear. The event forces her to confront and intimidate several police officers and hide Granma's fate from the rest of the family.