What does your lawyer say?
*I* personally don't believe that your X should be left alone with the kids (mine wasn't diagnosed but he displayed all the traits for narcissism), but the courts may not see it this way. In their minds, 4.5 hrs a week isn't much AND he hasn't harmed the kids, so why deny him his god-given right to mess up his kids? Can you offer to have a neutral third party supervise the visitation?
As for the 800K you supposedly owe him, ...well OF COURSE you owe him. So does the rest of the world. He's a narcissist remember? If anything, I think THAT claim is the one that'll be thrown out.