I had a cousin like this, addicted to alcohol and heroin, she lost custody of her two sons, one went to his father, the other one was relinquished to her parents to raise.
She was a complete mess, lost all her teeth, was stealing and prostituting, her parents and other family members helped her so many times but nothing changed.
In the end her parents went to live in Spain with the eldest boy because he was being badly affected by his mother's drug use, the rest of the family had to turn their back and refuse to help, because in effect she had to reach absolute rock bottom, and by helping her out all of the time the family was enabling her to carry on her chaotic lifestyle.
She did eventually admit that the problem was too much and sought rehab. This time she stuck it out and has been clean for eight years. She now has a full time job in a rehab, has a good life and is married, has reconnected with her children, but it took over 25 years of drug and alcohol misuse before she turned the corner