Can You Sue the Family Courts?

My best friend is wondering if she can sue the family courts system. Several months ago her volatile relationship with her sister blew up and her sister falsely accused her mate of touching her child. She did this through a hotline call and given the nature of the complaint, her children were taken from her and given all the rights that are listed on the Division of Family Courts pamphlets, all efforts are to be made to keep the children i the home if the "said perpetrator" does not reside there. Her mate and her have never shared a home at any time and although the case against him went no where (the child of course could not understand what they were asking, and they caused the child alot of distress and now she has been away from her parents for almost four months). The sister wrote a letter retracting the statements and they would not allow it in court. Now the mother, who has not been charged with anything at all is still without her children, had to be subject to court ordered parenting classes, psuchological examinations, all of which she has passed as she is a loving mother with no history of child abuse, neglect, nothing- and they are making her still go through this in the absence of no charges at all. When you look at the court order they got from a judge to get the childre out of the home, it also states that her mate lived there, which, not to tell all of her information, she lives in a not so great part of town and he makes six figures and lives in the cushy suburbs and has lived there for ten plus years! Is this all legal? Can she sue them, and if so, what kind of lawyer would she need? All answers are welcome.