Sorry to say this, but your daughter is obviously following the beat of her own drum. I'm sure it must be difficult to have a child that has become so detrimental to her own life. I know you mentioned her addiction, but does she have any mental illnesses? If she has any that are left untreated, she could unknowingly make some terrible choices. I'm concerned about her because of her recklessness with this man who may have HIV/AIDS. Not saying it is wrong to care for someone with that illness, but to become sexually involved is a very risky chance...
This might sound brash, but honestly what I would do, if I were her mother, would ask her some serious questions and let her answer each one. I would start off by telling her not to tell me what I want to hear, but to tell me how she really feels.
Why do you continue down this path of destruction?
How can I help you make this better?
What are your children going to think of their mother if she keeps making poor choices?
Do you know what HIV/AIDS are? And do you know how that would affect your life?
Good luck to you, I wish you and your family well.