General Discussion
In reply to the discussion: An update on my maga coworker [View all]wnylib
(24,450 posts)trait of always believing they are right about everything. It might work on your co-worker.
It's called "grey rock." You say only what you need to in the course of the day. Be bland, neutral, superficially polite, and professional about it. You go grey and bland as a rock. Keep all your communications with him strictly professional and grey. No small talk. No disagreements. No feedback except the most minimal necessary to do the job. The rest of the time, ignore him as if he is not there.
He might escalate for a while in trying to get a reaction, but hold onto your grey rock behavior. He will give up when you don't give him any attention. He might turn to someone else and you will still hear him. Maybe keep a favorite tune in your mind to distract yourself from his rants.
With luck, maybe others will catch on to what you are doing and imitate it.