Thanks for writing to H.C.M. for your query.
I have gone through clinical history of your mother as she had been operated for her ear problems and her ear is still leaking some fluid and she feels pain also. Post operative discharge usually seen in following conditions-
(1) Recurrence of pathology- As found in cases of cholesteatoma
(2) If operated cavity is not properly healed and is being occupied by unhealthy granulation.
(3) If mastiod is operated by low canal wall technique than operated cavity remains in touch with external canal so time to time chances of infections are there.
To manage this your mother is advice for these investigations-
(1) C.T.scan of ear (H.R.C.T.)
(2) Culture and sensitivity of ear discharge
(3) Blood - CBC, blood sugar- fasting & post prendial, Serum proteins
By the inferences of above investigations and their clinical co-relation one can find out the real problem which accordingly may be plan for treatment.