I hope that you are right that the boyfriend will be gone. Did I miss some of your posting? Is your son in the picture? How many of the children are his? Is the boyfriend the father of the coming baby?
My daughter has had children with two abusers whom she is no longer with. She does better emotionally when she is alone, but worse financially. My experience is that whether she is with someone else or not, she has never become a responsible adult (despite being a college graduate). After rescuing her for years with only momentary gratitude and subsequent verbal abuse and no interest in my welfare, I had to stop doing for her what she must learn to do for herself. I want only the best for her and her two children but not at the expense of my own physical, financial, and emotional welfare.
Sending positive energy your way.