Does cps have the right to lie, when are they considered breaking the law or unethical?

Threating to send a 16 year old child who is a good kid, honor student, in church admired and loved by everyone to a mental hospital for eleuation for a month, or longer,because she is refusing to live with her mother, it's not only cps it's also her court appointed lawyer,Can she sue cps for making threats to her for this and also making herself her sister who is 14 return to that home? How far is cps allowed to go to get their way and what can be done to stop this unethical and illegal behavior?