Dear Shelby,
Clearly, this is an essay question requiring a written response from you. The best advice is to review the novel and mark the important pages where Miles Hendon appears with sticky notes. Re-read those pages and make notes about Miles's behavior to describe his heroic qualities. At the same time, examine those passages for evidence that he would have behaved differently had he been a "true" hero. Usually, characteristics of self-interest prevent people from acting as heroes. Find examples of Miles's "flaws" and instances in which he could have been a hero, but didn't act as one. In answering these questions, you will define what a hero is in literature. Most literary heroes from Homer's Ulysses onward have flaws, especially because they are human. For me to provide you with my answer to the question would be for me to write your essay for you, and I regret that it's not my job to do that. I can only enlighten you about the process. The process will always involve a careful reading of the novel and thinking about the characters and their actions, and also how they refuse to act or refrain from acting. Best of luck!