Pregnant SIL..... 😢

My sister in law is now 39 weeks pregnant. At around 27 weeks we found out she was abusing OxyContin. She was taking A LOT. At that time her OB mysteriously dropped her as a patient (she says bc she refused a sonogram, but maybe he suspected something). She since found another OB and she has no idea.
She has successfully weined herself off, but I'm still so worried about the baby. Yes, it's a category B drug, but only when taken in prescribed amounts...normally. Her goal was to be off it a month before the baby was due so hopefully no one will suspect anything and it will be out of her system and the baby's. She also has a 2 year old. I don't even know what to do. She's due next week.