If it's *just* sleep issues and not any underlying conditions, just take Melatonin on the tough nights like Kiara does and focus on de-stressing 4 hours before bed. Melatonin is OTC in America, and doesn't require a prescription like say in Australia.
Not a doctor, but I was a Navy medic.
Now if she's having anxiety or depression also, that would be time for a doctor to step in and prescribe something. Could kill two birds with one pill if she gets on the right one.