Can I request an extension for my mother on her B-2 visa due to COVID-19?

My mother is 78 year old and she is been in the US since December of last year (as a visitor B-2). I am a permanent resident and soon to be a citizen. My mother is still during her 6 months of allowed stayed. We were planning on having her in the US with me for 6 months and return to Peru (where she lives) with my brother for the other 6 months. Due to the COVID-19, I am afraid of making my mother fly with me, as I am 55 years old and I also have health issues. Also, as right now, Peru is not allowing any international flights arrivals. I was wondering if it is possible for me to ask for an extension for her to legally stay in the US for more time? I am concerned what would happen if I file for an extension and I do not get an answer before she needs to leave? She is supposed to fly back on June 15th. What could I do under this situation? I do not want her to overstay her visa, we have always done everything right.