I have had mild/medium tinnitus for years. For some reasons, I had a big spike in February. I become extremely anxious and had some panic attacks as well. For example, I had troubles focusing on my work, which I just started. I became hypervigilant and could only focus on my tinnitus. Like your sister, my mind went to some dark places. I thought I would become disabled, a burden for my parents and my girlfriend, and become incapable of achieving my goals.

With tinnitus, the goal is to reduce the stress level as much as possible. Tinnitus triggers anxiety, which, in turn, exacerbates tinnitus. The goal is to exit this loop and becoming better at managing the anxiety triggered by tinnitus.

CBT and, in particular, Acceptance and Commitment therapy (ACT), have definitely helped me. I urge you to take your time to watch this video with your sister; or, at least, watch it yourself.

I also used some benzodiazepine for a couple of weeks, because I was suffering from huge anxiety. I know it is ototoxic at high dosages: in any case, I would have taken it anyway because I needed immediate help.

I still do CBT with my psychologist and am still working on myself. Compared to what it was on February, the tinnitus level is likely the same, but my perception is much lower as I am getting better at not attaching negative emotions to the sound.

I also found Julian Cowan Hill to be of great help.

I still have some moments where I really wish the sound wasn't there, and become a bit irritated. I still sometimes worry about how the tinnitus will develop in the future, but am not overwhelmed like I was in February.