You should be able to get free mental health services for your kids; all should be in counseling. A licensed therapist can provide a letter with concerns and help the child voice his/her preferences. Your children are old enough that they should be able to do that.
I don't know if you want to involve child services, it can get sticky. But if your W has been abusive to them, maybe it will help. You can call and report the abuse and they will investigate without you having to pay the courts for an advocate. You could ask at these counseling places for advice.
I believe I will see the bounty of the Lord in the land of the living. Wait for the Lord with courage. Be stouthearted, and wait for the Lord.
