I knew someone like this.

It seems, in his case, to be a real illness that should be approached with real compassion. He does need help. He isn't crying wolf, imho. I don't think he's doing this with intent to hurt you.
Some people you can call them out on and it works. Some you shouldn't.

I am sorry I don't know how to approach a situation like this except in a non-confrontational way...you seem to know this...