I recently read a Divorce Custody decision in which there was an overabundance of proof that the Mother had grossly and maliciously interfered with the children's affections for their Father. Prior to the divorce he was a good husband and father but the Mother turned three of the children against their father (one became over 18) that the younger two who were in or near their teens had adopted the vilification of the Father and wished him dead. They refused any and all contact. The children had court appointed attorneys, there were therapists involved, a custody psychologist, interviews of the children with the Judge, Child Protective Services Investigations, Police Reports were the Mother drove the children to the police station and pretended she was just providing a ride, each side had changed lawyers multiple times and the trial lasted for over 12 days not counting the years of litigation leading up to trial.
The Judge came to the realization that in his opinion and based upon what the forensic had reported and suggested that even isolating the mother from the children for 6 months could not undo the damage. The boys would hate their father even more. HOWEVER, the Judge awarded the Father custody of the even younger daughter thus splitting the children because it was the only way to try and prevent the Mother from doing the same thing to the daughter.
The summary above is abbreviated and may vary slightly from the lengthy detailed decision but the point is that if you have parents who just want to fight and ruin their lives and their children's lives sometimes even the judges cannot undo the damage.
Parents who refuse to pay child support or hide their income do damage of a different type and the courts have certain powers but again if someone is willing to throw their own life away for spite the courts eventually exhaust their powers as well.
The best advice is to think of your children and how to help them grow up with two parents and two families after divorce. Be proud of what has been accomplished not what was destroyed.