Well, if she were truly my best friend and I were hers, I woudl tell her that I was worried about her and her baby. I would offer to take her baby while she went into recovery and then give baby back when she was out.
Recently a baby was kidnapped from the hospital in Lubbock Texas, and brought here to Clovis. Her mother lived in the house right behind mine. Our houses used to be connected and we share a backyard. It was so scary for the mother of that baby, that I don't think I could ever kidnap a baby. Just because her mother is a drug addict, doesn't mean she doesn't love her child and wouldn't be frightened if the baby vanished.
Also, if I kidnapped the baby and then got caught, the police would return the baby to the mother and put me in jail where I couldnt' help my "best friend"
If my best friend wouldn't allow me to take the baby so she could go into recovery, then I would approach an assistance agency like CPS, and tell them what was happening and let them know that rather than put the child into foster care, (which they like to avoid at all costs) you would be interested in taking care of the child while the mother was recovering. I have a friend who is taking care of her friends daughter while she is in Rehab. Often times, after the state approaches the mother with her problem and their concern for her child, she will let her friend help her because she has more faith in her friend than a stranger who may only be taking her child in for the money the state will pay.
If you were roommates with you ex and then you both decided to allow one more roommate to move in but then your ex and the new roommate hooked up, making the house horribly uncomfortable, would you ask them to move out?