Hi Helen
Forgive me if I sound too cynical.   I think it is common for a CG to feel ill instead of starting something that might lead to them facing a lot of things about themselves that they don’t want to face. In fact I can see why that would make someone feel in.
Watch for excuses. They are understandable but we have to stand back sometimes and weigh up whether the will is there or not.  
Hopefully it is.   Nothing will make her better than controlling her addiction though, even if she doesn’t know it.