So, we had the conversation. Now I'm even more sure he thinks he can make things go well when he can't, but he is insisting on having her over. So, I told him that if things go south as judged by me alone, I am taking our child to a resort to play in their lazy river and that I then expect him to protect our house and deal with any authorities as needed. He said he understood, but I can see he is so sure crazy won't break out that it is I who am overreacting, so this is probably not real understanding. That's ok, I was clear ahead of time both about the wisdom of this, his inability to control the outcome, the potential for this to do the exact opposite of what he wants, and what I will do when I think the situation is no longer acceptable. When it all does go south and we go to a resort, he can be angry but he can't say I didn't warn him. He chose not to listen.