Thats a terrible situation.
Sounds like you need to focus on the best for your children, and yourself.
There is sadly not much to do for her. If you try and help, it will just make matters worse.
Can you create some consequences for her, like kicking her out of the house so that your children don't have to be exposed to this? Its terrible for them to be around her in that state.
Also, if you are working, and providing a home, and money while she is drinking all day, thats really quite enabling her behavior isnt it?
There is no way that I would leave my kids with her. At all.
Stay on this site. Lots of advice and wisdom here.