I agree. With that attitude going in, it will not accomplish anything. Maybe I'm a little cross-eyed but it makes little sense to me to criticize him for not setting it up, and at the same time say that it's not necessary to engage a mediator.
From what I saw on Dr. P, they cannot have a normal conversation, and it seems to have been the pattern for a long time. Strange to me to think that two people who once loved each other and created children together could end up with so much animosity and resentment between them, that they could not find a way to come together to find their missing child. I don't understand that at all, but if they have not been able to talk for the past six months, then they never will. So in all fairness, maybe she realizes that and is opting to avoid any more unpleasantness.