"Do not offer sympathy to the mentally ill; it is a bottomless pit. Tell them firmly: 'I am not paid to listen to this drivel. You are a terminal fool.' " - William S. Burroughs.
What that means is, the guy has issues you are neither equipped, nor required, to deal with. It's not much different than being in a relationship with a drug addict or a serial abuser. They are all psychic vampires who will drag you down with them at every opportunity.
Don't fall for the hero trap - nothing you say or do is likely to straighten this character out. Unless you want your life to turn into one long episode of Dr. Phil, you really only have two choices: accept it and let the BS run over you like water off a duck's back, or walk away.