I think that Cory being a writer enables him to be in a position where nearly everyone with whom he interacts can be in a position to serve him as being an example of a life lesson. For example, Cory learns from Johnny Wilson how strength is an internal quality that should be summoned and not forgotten at the most critical of moments. From Dr. Lezander, Cory learns about how outward appearances might be separate from the reality that lies underneath. In the Branlin brothers, Cory learns about the nature of evil and that which needs to be repelled. From Ben, Cory learns about the private sense of strength that is needed in order to counter the elements that life offers to specific individuals. In Vernon, the lesson of social solidarity is something that Cory absorbs. The characters that are present in the story as well as Cory's need to understand them in light of his own life help to drive the story. They also demonstrate how life lessons are evident in the people we interact with every day. From Cory, we learn that the people in our world can possess lessons that help us to understand both our world and our place in it.
Thanks so much this actually really helped me understand the book better!