My children actually went to a family court mediator when they were 15 and 12 to end contact with their father. I met individually with the mediator, as did the ex and his wife. I told the mediator that I had been doing damage control for years, but at that point, I was afraid that there would be nothing to save, no pieces to put back together. It's been 6 normal, stress free years for my children and me. Safety of the children is the number 1 priority.
You might try mediation or a GAL. As over-extended as the courts are, I was told that he would have to put one of the children in the hospital before family court would even consider hearing the case. Thank goodness the courts are looking to mediators to take some of the work load off the courts.
I hope you can get this resolved soon. Everyone will be better off.