Where in the world does your mom live that she's so far in miles and time away from decent healthcare?
I hope your brother is feeding her healthy food and she's drinking lots of antioxidant teas, but mostly, that's me being a busy body. I hope she recovers completely and soon.
My husband and father-in-law both got Covid. Husband was vaccinated, F-I-L was not. Husband has fully recovered, F-I-L still has a terrible cough but both recently tested negative for COVID.
Husband is at his dad's 24/7 when not working, so we were not infected.