Also, if only for my own self reflection as I don't want to project myself into eldest's place just because we're close in age.. Usually the delusion was "I'm going to moderate now" based on various imaginary rules and conditions I'd set for myself. It wasn't until the end, maybe the last 9 months that I was making real attempts to stop completely.
If she's really in that stage of awareness you have a real chance of getting through to her. It's just a delicate act to maneuver when setting boundaries.. I was talking to my sister about her bf who died of a heroin overdose.. and how his mom was a chemical dependency counselor (I'm not sure if she herself was ever an addict but to me sounds like there were major co-dependency issues). She said his mom was really good about not enabling him.. but from what I could gather, what that usually meant to her was giving him things and then taking them away if he didn't do what she thought was best for his sobriety.
If you've fulfilled your end of the bargain on everything you've promised her (support to help financially if she's in school, giving her a car so she can get around, etc.) I'm not saying you should rescind any of that.. but you can control the conditions in which you give her anything else from this point on, only giving them if she fulfills her end. That doesn't mean it has to be manipulation, it can simply be self-respect and/or self-protection. It also teaches her how she should be treating herself. In the vast majority of cases chronic addiction is not self-sustainable. I don't think rehab is always or even usually necessary, but in her case it might be if for no other reason than she's going to need somewhere to live. Chances aren't great that early sobriety will make it easier for her to support herself initially.
Anyway, I'm not doing super well with this quarantine. I'm pretty on edge and slept through my window of opportunity for my daily walk today. These are highly unusual circumstances and I agree she has plenty of reason to be anxious, so now might not be the best time to make or discuss major changes. Sorry for the long post but I literally have nothing better to do at this point.