Need help! Stepmother seeking advice to help father obtain custody of his 4 year old daughter!?

Need some help! My boyfriend is trying 2 obtain custody of his 4 year old little girl. The mother is VERY unfit & is n an abusive relationship w/ her husband. CPS & COPS have been envolved but nothing has happened. The mother cant keep a job, shes lived at 4 different houses just this year. She has asked us 4 money 4 groceries, my mother n law washes all of the babies clothes now (plus a couple of the mothers and her other childs) because she has missed school because she doesnt have clean clothes. When we bought her 15 uniforms (shorts, skirts and pants to go with each shirt), plus ALL of her school supplies. Her mother doesnt have a vehicle or a phone. So my n laws pick her up & take her where she needs 2 go. We r paying 4 daycare. We r the ones who take her 2 the doctor/dentist and go to her school events. The worst part is a month ago we had her & she said her step dad hit her & her mom told her 2 keep it a secret because it was a bad secret. WHAT DO WE DO???