I agree with Dr. Vinod kumar.
Your mother has pain and swelling in the ankles which could be due to inflammatory arthritis (eg. rheumatoid or gout) or secondary to other conditions like varicose veins and
diabetes.
You should consult an Orthopaedic surgeon who may get her Xrays, blood tests for arthritis and other necessary tests done. Further treatment will depend on the outcomes of these tests.