can i help my boy friend get his daughter back from cps and get at least parcial custody??

My boyfriend lost his daughter to cps in '09 when she was only a few months old. From what i was told by many people, the mother of the baby was holding her in her arms while trying to cut my boyfriends throat because she was angry with him. The cops were called and cps got involved. At the time my boyfriend and the mother were on drugs and failed a few drug tests. Cps would NOT let anybody that knew the two have custody of the child and also told both of them that they either had to sign their rights away if they ever wanted to see their daughter or the state would terminate their rights. My boyfriend has been clean ever since then, has a job, and a house that he shares with his friend. HE very much wants his daughter back and i want to know if i can help. we also have a 1 and a half year old baby together and another one on the way. I have my own place and i am a stay at home mom. I am very capable of raising children even if they are not mine as i am helping raise my nephew as well.