She should notify the board right away- it will look better for her if she goes to them rather than waiting for them to come to her. Not sure if she will be able to practice in the ICU again- depends on what type of restrictions the BON places on her license...
She is going to have a hard time getting a license to practice in another state for a while- all states require her to reveal whether or not there is any disciplinary action against her current license, and I doubt another state will issue her a license while there is an ongoing investigation for drug diversion...
She should also voluntarily go to a treatment program- her taking the initiative to do this before being "forced" to by the BON will also be better for her.
You should seek family counseling as well. Make sure that you are not being co-dependent and making excuses for her. Having tooth pain does not justify stealing narcotics and using on the job. She needs to take responsibility for what she has done, and you making excuses for her or saying it's not a big deal because she only did it twice is not going to help her. Sorry, if that sounds harsh, but what she did is a big deal, and she needs to be held accountable for it....