Help With Child Death

Location: Pennsylvania. Hi My family and I need some help regarding a child death. My brother in law had two children, the oldest A is now 3 and the youngest N was almost 2 at the time of her death. The BM and BIL do not have a custody agreement with the courts and they just did handoffs when the other asked. The BIL has been reporting to CPS for almost 2 years about the diaper rash and how sick both babies are when they come back from BM place. The oldest A had a broken femur at pickup a year prior to the event this year that went unattended until BIL picked the children up and took A to the ER. CPS investigated and found nothing wrong even though the BM told 3 different stories. With all that has been reported, in July the youngest N was found dead in the room where she locks them in at. We know that BM called her dad at 9am when BM found N, police at 1030am, and BIL at 1130am. To keep an already long post short, the toxicology has not come back yet but the da had picked up the case last week heard. The officer has told BIL that the da might not press charges and CPS has found nothing wrong even evidence of abuse or neglect in either of the children’s cases. We have shown all we can to show that BM neglects the children if not abuses them. She has people in the house that do drugs with her and abuse children. Two are suspected child abusers (we know they have they just were never convicted). BIL wants to go after her for custody due to all of these concerns and the state won’t let them file for a pfa against her because cps found nothing wrong with the situation. We know he needs a lawyer but they are expensive and he is scared to do anything that will let the BM have any custody or contact with A. I am concerned and would love if anyone could help us go in the right direction for who to talk to. Thank you in advance!!