Kathy I have been thinking about you and your difficult child a lot.... I am a little more clear headed myself this morning. So I don't know about where you live but here there are two kinds of committments, one is for mental health which would cover suicide attempts and that kind of danger to oneself or others. The other kind is for substance abuse and given that she overdosed, and could have died, I think you could make a case that her substance use is putting her at a danger to herself. Both kind of committments can happen through the courts.
Having gotten my son into so many treatment programs i don't know how much good it will do if she doesnt really want the help unfortunately.... sigh that is such a hard reality as we want to help them so much.
As far as risking your retirement.... I really dont think you should do this unless she is clearly clearly clearly at a place where she wants help and will really do the work to recover. If she isnt then I think it will be your retirement down the drain. I am coming to the point where I think the most important factor in recovery is them wanting it... and there are probably many lower cost options to help with recovery if they truly want it. I just dont think you should put your own financial future at risk, with so little assurance that it will pay off.
TL