Are you in the UK?
Have you or your daughter ever sought professional help before or any kind of help?
Maybe AA for your daughter and Al-anon for you?
Is she alone with her children everyday or does she work?
Is it because of alcohol that social services are involved?
I think unfortunately, unless your daughter wants to stop drinking herself, it is doubtful anyone or anything is going to make her do it. She has to want it and work for it.
It might be that she has not yet reached her bottom and until that happens, sad as it to witness, there is nothing you can do. Just protect and love your grandchildren. Make sure they are safe and happy.
I am really sorry for what has brought you to these forums, but hopefully you will be able to find a new way of tackling the problems your daughter has with new tools you lean here.
There is a friends and family section too.
Posting there may help you further.
My best to you and your family xx