My best friends controlling boyfriend, any advice?

I don't want to sound nasty but it sounds to me like you've already voiced your opinion to your friend and she hasn't done anything about it.If this guy is as bad as your saying he is why on earth would she want a baby with him!?As soon as she's got a baby with him he will be in her life forever because of the child.It is cruel to bring a child into this and she is not thinking rationally about it.I don't think you should get involved because I doubt it would do any good as clearly her minds set.Let her deal with this mess.But be a good friend for her when it all goes wrong and try not to be tempted into saying "I told you so".