First of all.....make sure you know more (about the pertinent subject matter at hand)than the person you're trying to teach

Sounds like you've got one of the old schoolers on your hands that doesn't appreciate the fact that they can still learn things.

These types are fun to play with. Back 'em into a corner with their own words and false information.....and laugh at 'em. Don't be surprised if the guy backlashes at you and personally insults you, though. It's a common defense mechanism.

Good luck with your new project!