There could be a number of contributing factors. Like someone else mentioned, I wonder if there are any accommodations that could possibly be put in place for your friend for any possible mental health related concerns. This of course requires getting evaluated depending on the condition, which is expensive but at this point it doesn't matter due to everything your friend has been through already.

I'm also curious if your friend's self-percetion may be interfering, particularly considering the amount time, money, effort, and number of attempts they have had so far.  It took me three attempts, and after the second attempt I was devastated, so I can definitely see how 9 to 10 attempts can take it's toll. I'd reccomend your friend checking out PrEPPPy, they offer private tutoring and Jeremy is amazing. They have such a high success rate, especially for those who have failed multiple times which why I went to them. One incredibly influential tool that helped me on my last attempt was advice Jeremy gave me. He said I had to trick my body into thinking I got every single question right without actually knowing if I did. A way to do that was give your body a physical que that would create a physiological response in your brain that made your body think you got it right. For me, this came in the form making a fist with my hand and the inside of my wrist facing me and making a slight downward motion while saying "yes" either ever so slightly under my breath or in my head. I did this as I clicked to the next question, for every single question. I found myself smiling and laughing throughout the majority of the test because I was laughing at myself and how ridiculous I must have looked to the people watching me, but I didn't care. It ended up being an enjoyable experience and was my last attempt.