In building or expanding our medical kits, an understanding of what happened to Brandon should be one of his life's markers. A good marker, that saves life, even if he lost his.
Close up (within less than 20 yards depending somewhat on "choke") a shotgun wound is "cookie cutter". That is, the shot column has little if any chance to widen and its kinetic energy has not reduced significantly. Which translate into "removal". Any flesh in line with the shot column is going to be either jellied or simply blown away with the passing shot. Effectively removed. In an instant.
Not being a coroner or having seen Brandon't report, I'm left to guess that he succumbed to blood loss and shock, not actual vital organ damage.
Question: would one of the quick-clot applications available have kept him alive long enough for surgeons to repair the vascular damage and save his life?