Does stepmom have any rights?

My sister married a man who had a 1 year old son. The mother lost custody and is pretty much worthless, she gave the baby up. The baby has known my sister to be his mother for over a year. She was a full time mother but then she had to get a job and is still the one that takes care of him while her husband collects unemployment and plays PS3. They were going to get her to adopt him but they haven't made it that far yet and now their marriage is ending. My sister is heart broken to think she may never get to see this baby again, who is like her own child. Is there anything she can do, any way she would be able to get some rights of him? He had a very hard life so far and my sister saved him. He was abused and neglected by his birth mother, and he would never show any emotion to people or even just play and act like a kid. Since she has been in his life he has come out of his shell and is a happy and healthy 2 1/2 year old. It really is in his best interest to have her in his life. She is so unhappy but the child is the only reason she hasn't left yet. Thank you.