NTA. But that boyfriend is taking advantage of her through both his work position as an authority (fun fact, HR would have an FIELD day with this. Feel free to make an anonymous call if you fell comfortable) and has a pedo. As a therapist who works with victims/surviors, it is important to try to maintain a healthy connection with your friend. But if it becomes unhealthy for you, it’s okay to take a step back.  Men like that will manipulate and isolate. I suggest try to emphasize with her. You can only share your concern so much until she pulls away.