In answer to your question,
it is lucky that he did not suffer major organ damage, but I wouldn't exactly say exceptional.
6 inches into your abdomen by a blunt object... I would worry about possible damage to intestines sure, but those tubes in your belly are also very umm..."wiggly"...
With penetration into the cavity by a foreign object like that without organ damage, the next most immediate worry of mine would be peritonitis. That could kill you.