Hi there,
It appears to me as though your mother is suffering some sort of occult infection, which means that we know that there is an infection, but the source is not obvious. At her age, a
low grade fever is significant, because sometimes they do not even develop a fever. The two most common sources of infection for her age group are
pneumonia, especially if she is not very mobile, or a urine infection, which she may not have noticed.
The fact that she is nauseous and getting excessively drowsy is a worrying sign of possible
sepsis, and I would advise you to bring her to an emergency room for them to investigate the source of infection. There they can perform an X-ray to check for pneumonia, a urine test to look for infection, and also run some blood tests to look at her sugar levels, blood counts, and
kidney function. They will probably require her to stay in the hospital for a few days until she regains her normal level of alertness and speech.
Don't wait any longer.
Hope this helps, and all the best to you and your mother.
Regards,
Dr. Teh