THIS - exactly right.
I have it from too much loud music. High pitched wheeeeee. Lost my high frequency hearing-- especially in my left ear because when I went to shows in college, I mostly for some reason was always up front stage left. My brain's trying to make up for those lost frequencies. I got hearing aids and they definitely helped. That said, I can deal with the tinnitus when I don't have em in too.
Psychologically, the thing about Tinnitus that's stressing yer gal out is the fact that it sets off fight or flight 'alarm bell's' in your mind. When you can quiet those and accept the tinnitus, it ceases to have much affect on you. I hear mine right now as I'm typing - but it's just there - no biggie. How I made it fade into the background for me. Get a white noise generator or a long, loop recording of forest sounds with frogs and crickets, a waterfall, or a rainstorm - something soothing. You can download that stuff from iTunes and just put it on loop. When she goes to sleep, have her wear earphones or if you can handle the sounds, just play 'em over the speaker. The "white noise" should be just loud enough that she can also barely hear the tinnitus as well. If it completely drowns it out, this won't work. So have her adjust the volume so the white noise is loud enough to partially 'mask' the tinnitus sound. Because the white noise is non threatening and background noise, your brain will start to also turn the tinnitus into background noise. Right away, it makes it so you can sleep, but also - over a few weeks (for me) or more, it makes the tinnitus just another background sound. Nonthreatening and easily ignored.