For me it was recognising that premies weren't really any better or more peaceful than everyone else, that actually they were a lot more screwed up than most. (Plus reading the New Testament and finding how solidly it contradicted M's claims.)
I doubt there's any way of forcing a change of mind; but if you live a good and full life, enjoy yourself (yeah, I know--like that's easy) then maybe someone will notice you've got just as much "peace" as he has, that you are more in contact with life and reality than the tired and pathetic bunch of deludes he meets at events.
I'm sorry I can't be more definite.
He's a lucky bastard, having you.
Neville B