* To show that Darry is not afraid of a challenge. Darry is a tough guy, and he is not afraid to stand up for himself or his family. By confronting his old high school buddy, Darry is showing that he is not afraid to face his past, even if it means facing someone who might want to hurt him.
* To show that Darry is still loyal to his friends. Even though Darry and his old high school buddy have drifted apart, Darry is still loyal to him. He is willing to put himself in danger to help his friend, even if it means risking his own life.
* To show that Darry is a complex character. Darry is not a one-dimensional character. He is a tough guy, but he is also loyal and caring. By confronting his old high school buddy, Darry is showing that he is a complex and well-developed character.
Ultimately, the author's purpose in having Darry confront an old high school buddy at the rumble is to create a more interesting and engaging story. By adding this element of conflict to the story, the author is able to keep the reader on the edge of their seat and wondering what will happen next.