Has she been ill? I'm assuming she knows how to properly warm up the vocal cords. I would absolutely consult with a physician on this and do so sooner rather than later. Let us know what they say!
I would suggest an ENT evaluation. Singers are prone to vocal fold pathologies. She would want to rule out vocal fold nodules or other problems. She would need a doctor referral to a speech pathologist who provides voice therapy, which offers treatment. There are some articles on good vocal hygiene to try in the meantime.