Has a father who has a history of violence and drug abuse the right to see his child?

Hi all,

I am here asking for a friend of mine who is worried sick about her child because the father has suddenly after a 2 years of drugged up stupers decided he wants to see his child again. She has been through an unbelievable amount of worry and heart ache in the past and so has the child. The father is basically a waster, drugs, crime and everything in between. She has turned her whole life around since the birth of her son and works hard to provide her son with the best life possible, she is so protective of him but has told me she wishes the father was the type she could even negotiate with on matters but he's never grown up and is on a war path. I told her there is no way a judge would make you leave your son with that kind of person but she keeps telling me otherwise and that she would have no choice but to. My question is, is that really the case? What kind of judge could live with himself if something happened to the child if put in that situation?

Thanks