If she was sitting behind the wheel of the car while she was drinking then she can be charged with drunk driving. Especially if the keys were in the ignition. Any one sitting behind the wheel of a motor vehicle is considered to be "in control" of that vehicle. You do not have to have the car engine on or be moving to be in control of a motor vehicle thus you can be charged with drunk driving.
Also many states have a law that if you apply and receive a drivers license then you must provide police a breath test or blood test upon their demand. Refusal to do so can result in you losing your privilege to drive. Remember being able to drive is a privilege not a right.