That child is so lucky to have you grammy. I hate to say it, but you will be raising her, sooner or later. Your daughter's addiction will only destroy her life more and more as time goes on. As you read more here, and possibly even attend some Al-Anon meetings, you'll learn that there is almost literally nothing you can do to stop your daughter's alcohol abuse...so please do your best to help shield and protect your GD from her mother's activities. Keep an eye out for your daughter trying to drive impaired with your GD, if you're able.
Again, your GD is SO lucky to have you in her life and in the situation. I don't mean to sound dramatic, but you've got many tough times ahead of you.
Feel free to stop in here anytime though! You'll find a sympathetic ear, validation, and understanding in nearly every member on this forum.