Grandma maya is the most intelligent and upbeat 70-year-old woman her family knows, but she has recently begun to dramatically mentally slip. based on the text research, the family might:

The correct answer is that "Her family might worry that Grandma Maya may have a fatal illness."

Since Grandma Maya was known to be an upbeat and an intelligent woman in her age, but as days pass, she begins to mentally slip, which may indicate mental illness in Grandma Maya, which is why she is needed to be brought to a doctor for diagnosis.