Arguing with Grant is completely fruitless, not sure why you guys do it. He'll never admit to being wrong, will twist words, cherry pick, etc. and even if you get to a point where he can't refute the fact that he's wrong, he'll just vacate the thread. You're never going to convince him of anything and are just banging your heads on the wall.
The correct thing to do is pat him on the head and tell him good job.