How did Bryon cope with Charlie's death?

Charlie is the owner of the local bar, and he is a good friend to Bryon and Mark. Bryon and Mark often make money by hustling pool in his bar, and at the beginning of the book, Charlie tries to help the boys by telling them to stop hustling. He warns Bryon, "You guys are going to get in real bad trouble one of these days."  In Chapter 5, Mark and Bryon challenge some Texans to a pool game, and, after the boys win, the Texans wait for them in an alleyway and try to attack them. Charlie defends them with a gun and is shot and killed in the process. 
In the aftermath of Charlie's death, Bryon feels incredibly guilty, while Mark seems unable to understand Bryon's emotions. To cope with Charlie's death, Bryon becomes more and more connected with his girlfriend, Cathy, who is intelligent and determined to make something of her life. Cathy understands the way Bryon feels, while Mark doesn't. As Bryon and Cathy spend more and more time together, Mark grows envious of them. Bryon becomes increasingly responsible after Charlie's death and gets a job at a supermarket, and he also deals with Charlie's death by going to the cemetery and thanking him for having saved his life. 

In Chapter 5, Bryon and Mark get themselves into trouble after they hustle a couple of guys from Texas in several games of pool. Fortunately, Charlie saves them by pointing a sawed-off shotgun at the Texans. While Charlie, Bryon, and Mark are walking away, the Texans shoot and kill Charlie. After Charlie's death, Bryon is devastated and feels guilty for hustling the Texans, which caused the conflict. Bryon mentions that he would only speak to Cathy and Mark about what happened. Bryon then becomes introverted and starts acting differently. He mentions that he failed chemistry and attempts to talk to Mark about the incident. However, Mark doesn't understand the significance of their decision to dismiss Charlie's warnings and simply believes that "things happen." Instead of continuing to talk to Mark about Charlie's death, Bryon copes with the tragedy by speaking to Cathy about it.