I suggested a very simple exercise that I use all the time myself.
Simply count 1 2 3 4 pause and then 5 6 7 8 . Do this over and over until you get to sleep. The mind can only concentrate on one thought at a time. If you simply insist on counting, which has no emotional connotations, your mind is soon turning away from anxious thinking and is lulled by the boredom of the repetitive counting.
The brain always follows the direction of its most current dominant thought. You make any thought dominant by insisting upon thinking it, repetitively.
She called me yesterday and said the technique worked. She did get to sleep much more quickly.
Another great thing about this dumb little exercise is that the more you use it, since the brain works by learned association, you actually create a neural connection with the exercise and the going to sleep pattern in your brain and the technique works more and more quickly the more you use it.
Another thing I do when my mind starts racing with thoughts when I should be sleeping. I ask myself "Do you want to think or do you want to sleep."
Then I do the counting exercise.