In my opinion the most significant event that transpires during chapters 13-19, occurs in chapter 14 when James is sent to live with his sister in Louisville, Kentucky. His time there is a crucial turning point for James because he stands on the precipice of ruining his life at this point of his story, and his time in Louisville allows him to reflect and change course. Importantly, an old southern alcoholic named Chicken Man is instrumental to James's understanding that James's recent turn towards crime, drugs, and skipping school will inevitably lead him to failure. Chicken Man is a stark reflection of who James will become if he continues down the road he is currently on, and thus James's conversations with Chicken Man coupled with his overall time in Louisville become one of the most influential periods of James's youth. .
James adds this story to his novel because it is vital to his personal growth. During James's delinquent phase, James feels resistant to failure and this causes him to behave thoughtlessly and recklessly. When James realizes that similar behavior has relegated Chicken Man and his group of alcoholic friends to spend their days sitting on a street corner, drinking, with nothing better to do, he is enamored at first, but soon comes to realize that this can turn into his own fate. Furthermore, his involvement with Chicken Man and the rest of the corner crew allows James to experience the dark side of black culture in a way that James would not have been able to do under the supervision of his white mother. Thus, James's time in Louisville adds a depth to the book, and to James's life, that would be missing within the framework of his family life alone. .
This event signifies a sort of "coming of age" for James because he is forced to realize that he is indeed not resistant to failure, and that his intelligence will not necessarily save him.