Please tell her mom that don't get depressed. Failure and success is a part of our life and your brother will do more hard work and give re-exam for obtain better marks.And also please contact your doctor they will give you better ideas. One more thing please don't leave her alone always be with her and try to feel her happy. Tell her to do yoga on a regular basis it will also help her a lot and reduce her depression. Let me know she feel better or not?