OP, not sleeping well with sleep conditions that have changed (person, bed, place one or all different) is fairly typical.
If it's truly developing into anxiety, that's a different story. While what you are seeking might help temporarily, I'll make another, admittedly unsolicited, recommendation.
Help her or ask her to seek out a good therapist. Anxiety has a multitude of causes and manifestations, but if she tackles the root cause of the anxiety, the long run can be better for her. It's not a quick fix (or cheap) process but it often times has longer lasting effects.
What you are seeking might be a bandaid in the interim, but if she can tackle the anxiety issue, I suspect it would be a bigger help.