The TSA have no clue. Unless they see a titanium pen they would like in their pocket. I carry as little as possible in my pockets on any flight. Wallet, phone, ticket. I put any TSA friendly items in my carry on so they will need to see it on the X-ray to question it. In your situation I would have had him call his supervisor/boss to confirm the "weapon" and tell him ANY pen can be used as a weapon. If he said it was dangerous because of the point, I would unscrew the tip and put it in his hand and ask "What now makes this dangerous?"
best tip so far (pun intended)