The only way to stop the brother from attempting to force greet is to follow through with "The Taste of Death" until you bring Verelus to Eola, then kill her. Essentially, it's the same outcome, with the addition of some gold from Verelus and the likely death of the other cannibals in the coven.
You can also try exiting the conversation while he's speaking; he won't try to follow you until he finishes his sentence.
It's a bit to late for doing that. I killed Eola in the hall of the dead. The process was alright as I told him that I took care of his cannibal problem and he gave me some gold.
It never ceases to amaze me how many glitches and bugs that is in this game.
Facepalms.
Serethil, I havent tried that but I guess I will have to try it.