i would make this my final line and then wash my hands.
sometimes these folks just have to hit bottom, and if it means being on the street than so be it. offering help once is fine, but over and over is simply reinforcing that someone will come to her rescue and it's okay to screw up again and again. the more exposure you get to her destructive nature, the more chance she has to manipulate you. if anyone is good at subtle manipulation to get exactly what they want, it's an addict.
now that i have a little one of my own, i have had to draw some hard lines in the sand with family members myself. it's sad, but i would do anything to protect my son from even the smallest hint of exposure to the things i had to deal with growing up. he comes first, period.
This is my thought also. She hasn't really come to me for much before... we just didn't talk for a long time. I decided to give her the benefit of the doubt when I moved back to town and she told me that she cleaned herself up so that she could get to know her grandchildren. From what I can tell, she is not on anything when I've been around her, and I've been around it enough to tell.
But she still does have this victim attitude and doesn't seem to think (or admit anyway) that all of her bad decisions in the past have her in the touch spot she's in right now.
She also didn't ask me to get her out of the spot she's in now... I just decided to do it because I think that if I didn't she would be asking for little things for a long time. And I also want to see what she does with the opportunity. The money that I'm putting out for this is not going to hurt me.
I also explained to her (b/c she said she felt guilty for taking my money b/c she felt like she was taking it from my girls) that if spending this money was taking away from my kids then she wouldn't be getting my help. I also told her that my wife agreed to this because I don't spend this much unless we both agree on it... so if she had said no, then it wouldn't be happening.
There is no chance in hell that I'd put my own family in any jeopardy to help her out. And I told her that she should consider this her last chance to get her life together, and if she didn't make it work that the streets are her next step.