During Air Force Academy’s graduation on Thursday, senior cadets will be told about the uncertain world they are entering and the battles they may face. It may be underwhelming for 22-year-old Parker Hammond. He’s already fought a private war. Hammond went from a strapping 275-pound offensive lineman as a freshman to a shriveled and shivering senior as he fought through chemotherapy. He battled cancer, and he battled bureaucracy to get the lieutenant’s bars he’ll pin on after he crosses the stage in Falcon Stadium on Thursday.