Hi Marteen,
Is it possible that she has stopped using but is not in "recovery"? I don't know much about bi-polar so I can't speak to that but you will no doubt have seen many posts here where a person can quit their DOC but without looking at the underlying causes, that nastiness can certainly surface.
As for your Granddaughter, well all you can do is your best at keeping her safe and that sounds what you are trying to do.
Sorry I don't have much insight to offer but wanted to welcome you back!