Sorry to hear about your sister being traumatized by the bad car accident she was in. I would suggest you encourage her to see a psychotherapist, especially one who specializes in hypnotherapy as that will help her heal faster. You can drive her to her appointments until she feels confident to be on the road again behind a wheel.
Dr. Lata Sonpal
It sounds as if your sister is traumatized. She will likely require professional assistance to help her work through the trauma. The avoidance of the feared situation is a symptom of the trauma, but also does not help her with healing. You can help by being patient with her, supportive and encouraging her to see a psychotherapist trained in trauma treatments, such as Prolonged exposure, Cognitive Processing, or EMDR.
Teresa Y. Chapa-Cantu, Ph.D.
Dr. Claire, PSY. D.
Nicole Grunzke, PsyDLP