From my discussions with psychologist, doctors and other professionals.  And, the fact that life is simply never a controllable, certainty filled experience.  I would have to say you will never know that she will be ok.  As you do not want her back, I know how hard the lying and nastiness is personally, there is little you can do.  If you would consider getting back together if she is stable, your only option I can think of off hand would be to tell her if she gets herself stabilized, you would get back together with her.  Adultery and all that has gone on, would make that extremely hard to do, and would certainly require relationship counselling.  If you have no contact with her or her family or her friends, you may have to simply accept that you will never know if she will be ok, and that she may not be ok.  After all right now if someone asked if one of your friends who is not ill, is alive, you'd say yes.  But you really don't know that.  Life is uncertainty, and sometimes as hard as it is we just need to accept that, and move on, and hope for the best in a situation beyond your control.

Get help for yourself if you are having problems dealing with it, the best thing is to get yourself to a point where you are happy and enjoying life again.  That you can work on doing, helping yourself, with her it may be there is nothing you can do anymore.

Best of Luck

David