Need advice to save a life

Hi. I hope this is the right group to post. I will try to make it short. I know a teenage girl (15) who lives with her mom, parents are divorced. This child has been going through so much. Her moms boyfriend is not someone safe she can be around, but the mother doesn't believe her. She was taken to the ER the other day because she was having some type of mental breakdown. The doctors told her she was fine. This child cannot sleep in fear of her mom's boyfriend. After she was taken to the ER her biological dad tried to get her seen by a therapist (he has no idea of what this child goes through at home) because the child asked for help. The dad was denied any information from the hospital and wasn't allowed to make an appointment for his daughter to see someone. The mother does not want to give him any information about her insurance or medical numbers. This child is screaming for help. She is slowly becoming suicidal. Her dad went to the social services office today and asked them for help in this matter. They turned him away and said he has to figure it out with the child's mother. When did a child's welfare not become a priority for social services? I am so scared that she might harm herself or someone else. Her dad has always tried his best to be there for her, but the mom doesn't let him. He pays child support and the child's needs are not met. She has the same clothes and shoes. She basically has to beg her mom for basic necessities. Her mom told her that she can't see a therapist because they only tell you lies and make you more crazy to take your money. Does anyone know what else we can do or who to ask for her to get her proper treatment? We live in California. Please. Any information will work.