...that is why I stopped speaking to, attempting to converse with, or replying to him in any way quite some time ago. And tried repeatedly to suggest others do the same.
I've suggested Christians pray for him because talking to him isn't helping. Whether people are being loving toward him, scolding him, trying to reason with him, being sarcastic with him, trying logic...it doesn't matter. Anything they say is just feeding into the problem. They need to stop.
He needs medical attention, possibly medication, who knows. If he is acting in r/l the way he is acting online, he has some really serious problems.
If prayer works, and he gets no other medical help, then it will definitely be a miracle.