My brother was an addict and sadly died at 20. My mother was completely overwhelmed by his addiction and it was very hard to see them both enmeshed in addiction/codependency.
Being ten years older than my brother, I lived 3,000 miles away and was darn glad for the distance from them. I had a family, a husband and two children so my energy and attentions went to them and for that I am grateful.
My ex enabled my AS for years and Our daughter felt she was not given her father's attention or interest because he was completely enmeshed with AS
and all his problems. Fortunately, I found recovery for myself early on in AS's addiction and did not repeat my mother's pattern and was fully there for my daughter. Without recovery a codie parent gets as sick as the addict.
The best thing you can do is make the most of your own life whether or not
"they" change. You can only change you and nothing you say or do can change them.
It's fine to give Mom a book on codependency and encourage her to seek help. Then leave her to find what she alone can change when and if she is willing.
Detaching for the sake of you and your family's sanity is very healthy. I found attending Alanon meetings gave me back my life, the one I deserved to have without rescuing, feeling angry about, worrying about, resenting or controling others. I suggest you attend meetings and keep coming here. We truly understand, care, support and offer a wealth of experience, strength and hope.