First - Whatever sent her off on this path, it wasn't pot, ok?
No, I'm not one of those people who thinks pot is completely harmless. But seriously, most negative side effects have to do with making people less motivated, except in young growing brains where it might possibly affect development. And it is far preferable to most of the legal prescription drugs that people medicate themselves with for pain or anxiety.
If you honestly believe that drug use set her on this path, it WASNT just pot. She had to have been using something much stronger (speed would be a common risk, often abused by overwhelmed housewifes either for "focus" or weight control initially).
I don't care for pot personally, but I do prescribe it for certain conditions, and it's far less risky than alcohol.
As for the lunch - it's good she's reaching out. It's bad she called the school. It's good she wants to be a part of their lives - it's bad she's not totally accepting responsibility for her actions and still wants the girls to accept her life ( which means accepting OM).
I'd be careful, do mostly listening, but have a specific path laid out if she asks how she can reconnect with the girls.
Also - don't know if it's legal where you are, but you might want to secretly record the conversation if you have any concerns that she might falsely accuse you of anything.
