Rant!

I have nobody else besides my hubby to talk to about this but he's honestly probably tired of hearing it. -.- so I know this woman. She has a 3 year old daughter. I babysit for her. When we first met we were best friends. Well her daughters father had left her to go live 3 states away and she seemed fine she was doing so great on her own then around tax time last year he came back and used her for her money and stayed and then since he didn't get a job she couldn't afford anything so we let them move in with us for a bit. And then he left her again and she has completely changed. She has been sleeping around with anyone and even when I tell her they have an std she still does it. Idk how to tell her that she needs to be more careful and that everything she does she needs to think about her daughter (who I provide stuff for) she's been a horrible friend and a bad mother and idk what to do anymore I can't tell her off cuz that's just immature. Help?? Lol any tips at all would help.