She isn't willing to go to any lengths, there isn't much we can do....
I have no experience with this. I do know that my prayers might help.
My sponsor was an atheist, but willing to set aside old beliefs and know that their way wasn't working, proceeded to move into the steps. The spiritual experience was real and today, my sponsor does have their own higher power.
When she is really ready to stay stopped, she will. Some kind of belief or willingness to believe is essential to working the steps (program or design for living) that is the AA way. Has she attempted Rational Recovery? AVRT? SMART? Women for Recovery?
I couldn't stop until I was totally desperate, hopeless, and beat down; and then I was guided through the 12 steps.