Newstart, my heart goes out to you and your husband as well. It must be especially hard to see your daughter like this when you have already lost a child. I am so sorry for your loss.
Me, too...that was me, young, dumb and socially inept. I look back and shudder at how unprepared I was for the life I was signing up for.
Sadly, with the genetic nature of so many of these problems, it seems there are many of us out here with multiple children off the rails. I'm just grateful for the relationships I have with the ones who are on track right now.
That's so sad that your mother continued to worry even on her deathbed. I'm afraid that will be me as well. (I'm even more afraid that I am likely to outlive my difficult ones, with the paths they are on now.)
I hope your sister manages to find peace and happiness one day.