She sounds a lot like my sister. Her marriage broke up, her young children chose to live with their father, she nearly lost her job.....
We tried many different approaches, direct, subtle, angry, reasoning; nothing worked as she laid waste to her life. She would deny she'd been drunk when you saw her falling down.
Eventually she met a guy who filled a need in her life. She still drinks in the evening, and shows signs of brain damage, but it's not as bad by a long shot. One son hasn't seen or spoken to her since he was 16.