If it's based on a word-of-mouth account written down many years after the war, elements of the story will be lost in translation. In this case, since we know Charles Haddox was just a little boy during the war, it could be that the original version had an older family member being a casualty at Brice's Crossroads. Perhaps it was his father. The story-teller may have used 'Charley' Haddox as a living reference, and over the years, after Haddox died or moved away, Charley's name was substituted for that of his long-dead relative. Just a theory.