It really doesn't matter.
All you have to do is tell him to go on Planet Complex and check out how many Cardiff related threads there are,
Show him the video of them singing about us at the last game at the Vetch and Tate singing about us on their promotion bus, Remind him about their petition about team of the year when we got to the cup final,
Remind him we've got triangular flags,
Remind him that they're rent boys - they don't own their concrete jungle that looks EXACTLY like Darlington's stadium (only it's actually smaller!)
Remind him that the Swim Away incident was over twenty years ago and yet it's still ingrained in Jack folklore, taught to children as soon as they're able to grasp the English language.
Don't hate the Jacks, pity them. Their only pride is in their hatred and jealousy of us.