I am so sorry for your pain. My 20 year old son is an addict in early recovery (10 months this time around). While I am not in your shoes right now, I have walked that path.
Loving detachment - for me- is a state of mind, not a path of behavior. It's about how I think- not what I do in relation to my son. Detachment, for me, is simply the opposite of being enmeshed with his life. When I am thinking about whether or not he's scheduled a doctor's appointment, is going to meetings, or is meeting with "old friends", I am enmeshed with his life - that is not detachment. When I am focusing on my own issues...that's detachment.
For me, being detached doesn't mean I won't feel pain or grief...every parent feels sorrow when their child hurts...but it does mean that the pain doesn't permeate my life every minute of every day.
Your daughter is in a very bad place, but detachment means that you don't need to be in the middle of it with her...even as you grieve.