As you asked in your post, nothing will stop her until she 1) wants to quit and 2) is ready to quit.
My mom (diagnosed in 2006) quit around 1988 after she was suffering with severe COPD, and even as I watched her struggle to breathe over the years, I continued to smoke until about a month before her diagnosis.
Smoking is such a powerful addiction - one that is very hard to overcome, even when we see what it has done to our loved ones.
You have planted the seed with your daughter, and hopefully one day, she will find the will to quit.