How does Dennis change?

Ruth and Dennis finally get together, "came from a home where kindness was a way of life. I wanted to be in this kind of family. I was proud to join it, and they were happy to have me." Dennis finally turns his strong faith into a vocation. He attends Bible College and they start a small church in their living room. They have many kids. I don't think that Dennis is really a dynamic character. He provides bedrock of support for Ruth throughout the story. Dennis eventually dies of cancer.