You need to take away the car keys. If she gets a DUI or kills someone, things will be much, much worse for all of you. Please take this seriously. This should be the consequence of her actions. She’s shown you she drinks too much and it’s no secret to all of you, so act on this!
She should get another job and get herself there. She’s needs to have a schedule and do something. But not drive around anywhere because she’s proven she can get into a drunk driving accident. Small steps. She should work and get a routine. For many, many people this is easier than school. Maybe she goes back, maybe not. Maybe after she matures a bit.
She may not need rehab, but she should not be driving.