I don't have anything to add to the advice you've been given here, wtbh. I do think that wearing a recording device of some sort is your best shot at this point. I just want to say how very sorry I am that things just continue to get worse and worse. You have handled everything up to this point as best you can, I know that. I assume the girls are still seeing a therapist....are you seeing one for yourself? The trauma must be taking a toll.
You and the girls will get many prayers tonight.