JOSEPH FLEMING, a decorated Korean War veteran who raised six children in Southwest Philadelphia, stayed in his neighborhood despite it taking a turn for the worse — only to be gunned down at age 80 by a young thug who broke into Fleming's well-kept corner rowhouse to steal his laptop.Wounded in the pelvis and the stomach in the May 17 home invasion and shooting, Fleming clung to life in the Hospital of the University of Pennsylvania's Intensive Care Unit for 36 days before he succumbed to his injuries on Friday.