The medical field got hit hard by the government enforced pandemic shutdown.
Elective surgery was not allowed for months (which accounts for a great deal of revenue) and primary care, along with other fields, had to decrease hours and the number of patients that were allowed to be seen (focussing on covid related appointments).
This resulted in people not getting the regular care they would've/should've gotten, but it also affected the medical employees with layoffs and severely reduced work hours.
Your mother has been out of work since April, so it sounds as though she may have gotten laid off. Or maybe if she worked for a private practice, the office may not have been able to financially survive the pandemic.
If the government forced shutdowns stop and all businesses can get back to normal, hopefully your mom will have better luck finding work. Take care.