[Willie Stark:] "He'll be all right." [Lucy Stark:] "God grant it." (9.298-99)
This conversation between Lucy and Willie is repeated several times as they wait to learn about Tom. Willie can't surrender his hope for his son to God. Yet, it's all Lucy can do.
But later, much later, he woke up one morning to discover that he did not believe in the Great Twitch anymore. (10.438)
Jack doesn't tell us if he found a religion to replace the Great Twitch. If the pattern of his life holds, Jack will continue to ponder religion for some time to come.