I listen to a counseling show daily and the host frequently uses a common example:
He likens a troubling situation to a medical condition.
In your case, FIB, I think he would agree that your kids are being exposed to some very dangerous behaviors. He would say something like: If one of your kids had cancer, would you spare any expense seeking out the very best professional in that field to diagnose and treat the illness?
He would follow with: Well, your kids do have cancer - the cancer of a mother who has lost her capacity to consider their well being at this time. Will you settle for second best in their treatment?
I'm in line with those who suggest rattling some cages in your camp. You need allies that will vociferously fight for your kids well being.
I know it's tough to separate the behavior from the individual, but at this point your W appears to be acting out of fear/anger and the most loving thing you could do would be to protect them from her. I can almost guarantee it that she won't see it that way though. Tough place to be. You are in my prayers.