Every step further from her is better for you
Back away sunshine. Each time you engage you get hurt. Just keep NC unless it's Kid related. There is nothing you can do here except look after yourself and your child.
I know it hurts.. God I know. But until she gets treatment she will not behave rationally. Its also gonna hurt when she stops reaching out. And it'll hurt when she moves on to someone else to enable etc. That's why you must back off for you. Surround yourself with loving people.
I just know how I did this to myself..