One day at a time, that's all that's required, so hang on to your boundaries and make the alternative clear.
When my son was "waiting" for rehab, I reminded him that recovery didn't begin when he was accepted, it began today with his willingness to do what he needed to do to stay clean. There are meetings, day programs and as much support as he is willing to grab on to, and today was always a good day to begin.
Hugs