The Lord kept you and your son safe, and He removed her into an environment where she can get the help she needs. Prayer's are always answered just sometimes not in the time or how we expected them to be.
I am truly sorry that you have had to go threw this, mental disease, or substance abuse, or even hormones can make us become someone we are not usually, as you said she is a very sweet women, and I don't doubt that for a second. She is so fortunate to have someone like you in her life, that loves her as you do.
She is going to thank you in the end for doing what you did, and handeling it as you have.