She needs professional help. She has attatched her value and identity to being the best but nothing will ever make her feel good enough because she is looking for external validation. She needs to gain some perspective on the real world and realise that grades are a fraction of what it takes to excell in the job market. She'll be competing against people with fewer qualifications but more connections or people who are charismatic, people who use their sexuality and connections. The top ten means so little in the grand scheme of life. Getting the qualification is what matters most and if she can't see that then I feel sorry for her.

Just give her a hug and say there there and also don't have too high of expectations for herself but just keep trying .. study more cry less 🙂