That was heartbreaking. And explains again partly why sosio-economic status inherits so strongly. Many of us are struggling to detach from our adult children as adult people with lots of experience of life. It is so much more difficult to detach, when you have no life experience, are on your teens or early twenties and have been always taught how you are everything your parent has.
Luckily my mother's substance use was abusive only at times. And she was very high functioning on certain areas of life and in certain times. And I had my grandparents, who were stable enough and supportive, when my mother let them be part of my life. And some of my step dads and her boyfriends were good guys. But still being an adult in mother-child relationship from early on was very taxing. And detaching in later teens/young adult wasn't too pretty.