Wow
This is a hard decision, I imagine.
I am thinking of this way...I would not give a suicidal person a gun as a gift. I would not give my toddler a knife to play with.
Unless your daughter is able to become sober, I can understand your apprehension about giving her the car (even if it's a loan, it's for that purpose).
By putting that "weapon" into the hands of a person out of control, it becomes predictable/expected that they could hurt themselves and OTHER
PEOPLE in an alcohol related accident.
I don't know...my reasoning may be out of line/skewed but I would feel hesitant just as you do.
Perhaps the responsibility of taking control of her own life, getting the drinking under control and earning her own money for the car would be a good thing.