Firstly, welcome to the site.
This is like de ja vu!!!!!! (I am a fading ex-J.W. by the way)
I had a long term connection with a girl who was in exactly the same situation as yourself. She tried every way possible to get the love of her life to waken up to the fact that he was in a cult. After two years of anguish, she was dumped and he returned to the family home! She is now recovering from her lengthy mental trauma and ditching.
Unless your boyfriend can see - and admit it to you & himself - that he's been immersed into a cult, then do exactly as St. George of England advised, run like hell!
I hope your choice comes easily and quickly - whichever way it goes.