What causes Lewis to see his father as a fallible human being?

As a young boy, Lewis saw his father as an infallible hero. After Chesty's stroke, Lewis begins to see a different, more fallible side of his famous father. Without troops to guide, Chesty lazes about the house, searching for a purpose. Lewis begins to resent his father's lack of motivation. As Lewis grows into his teen years, he realizes that he is becoming physically stronger than his father. However, Chesty's vulnerability also brings them closer together. Lewis learns that he can now talk to his father as a man. The two men develop a close relationship that lasts throughout their lifetimes.