The tooth can be saved by RCT or may be extracted to permanently cure
your mother's problem, a scaling and polishing mey be required after professional examination. Meanwhile ask her to take antibiotic amoxiclav 625 mg 3 times daily for 5 days after food and diclofenac
50 mg when needed. It qill prevent tooth infection
to spread and complicating her problem. Let her use a chlorhexidine mouthwash also twice daily to have an additional check on oral hygiene.