Well, from personal experience, to me that meamt it was time to look the other way and have as little interaction as possible, but with kids, that didn't work so well. I see you don't, so, that should make it all the much easier to just let her be and carry on with your own life while she does what ever it is she needs to.
Me 35/XW 33 S13 & S12 M: 10/17/98 OM & S: 07/08 D final 06/09/09 12/03/09 - 06/13/10 "Piercing" 06/13/10: Engaged to Re-marry 10/17/10 06/25/10: Expecting baby #3 2/14/11