Thanks for your query,based on the facts that you have posted it appears that your mother has increased frequency of urination and dysuria
since three days.
Please get her routine urine test and urine culture done to find out the organisms causing this infection and antibiotics to which they are sensitive to.
Please take broad spectrum antibiotics like Cefotaxime
along with urinary antiseptic like Nitrofurantoin
twice daily and urine alkaliser thrice daily.and later on switch on to appropriate antibiotics as per culture report.
Get the prescription of medicines from your family Physician.
Ensure that she drinks more water.To keep her urine dilute This will help to control dysuria.