Many potential causes for loss of the sense of smell. Check into fungal overgrowth. She have mold in the home? Prudent to get her tested; mycotoxicosis may be in play. Left unchecked the potential for problems down the road (e.g. parkinsons via ochratoxin) grow. Don't worry, just don't overlook microbiota causes for chronic disease. Dig on Doug Kaufmann. Good luck.