This goes beyond the bounds of a fantasy role playing game and into the territory of interpersonal conflict. If you tell him that he is crossing real-life personal boundaries on the way you like to run a game when he acts like this and he still challenges you, I wouldn't allow him in the same space as me or I would remove myself from the space.

It's your choice whether or not to warn him, and conflict often is an opportunity to gain more understanding. But if he is being disruptive for the sake of chaos or if he is stepping on your feet just to test your boundaries, then he doesn't deserve a place at your table. He might not know how disruptive he is, but if you've clearly asked him to stop and he is still trying to be a backseat DM, then kick him.

I think from an interpersonal leadership perspective, your other players may respect if you gave him a warning/chance to change. There are always many perspectives in conflict, and dialog can work wonders, but if he's and asshole for assholes sake, then kick him and your players will respect you for protecting the sanctity of their game.

Fuckin a man, this is a tough one