I tend to argue very little with family, simply because I don't want to cause undue tension. As for why carry everywhere-you never know when you'll need it. Why carry open? Answer his question with a question-Why hide it? Then give standard arguments such as OC is a deterrent, faster access, comfort, etc. If he says anything about someone targeting you, provoking you, etc., simply ask him to point out where it has happened. It's very rare.