D..
I have this problem too, but mine is mostly menopausal induced. And it bothers me when I'm dealing with stressful situations or people.
Most of the time I am here on MP when I can't sleep! It helps break the cycle of what's running through my head. When I start to get sleepy, I put the computer down and go to bed. That helps me.
That being said, I don't think you should put her on the computer, LOL!
Instead, get her this book: A Little History of the World by E. H. Gombrich.
http://www.amazon.com/A-Little-History-World-ebook/dp/B00...
It's easy enough to read that she will be willing to do it. It's not exciting enough to be riveting. It will teach her something while she's reading it. And it will do what MP does for me, breaking the cycle of not being able to stop thinking about what is bothering me.
Try this. I really think it will help.
Dawn