I'm so sorry that you're dealing with this around the holidays.
I am also the mother of an addict (son) and have watched his life spiral out of control for 15 years (since he was about 15 years old). It took a very long time for me to let go and find something that resembles detachment.
It sounds like you are taking some very important steps to protect yourself. For me, meetings (Al-Anon and Nar-Anon) and the people I have met there, have been my saving grace.
You and your dear daughter will be in my prayers. We don't know what the future will hold for our adult children. God works in very mysterious ways. I do believe that things happen for a reason and time will reveal those reasons. Patience has never been a virtue of mine but I am learning those lessons....slowly.
Take care of you.
gentle hugs
ke