How To Treat Severe Ear Infection Leading To Pain?

hi,My father has chronic diabetes, hypertension, angioplasty twice(2002 and 2006), nephritic patient with eGFR 55 aging 79. Now he is suffered from ear infection for four months.Even after the series of medication he can not be cured. He needs a major operation but doctors and anesthetist are not ready for his operation because of his age and other health condition. He is suffering from pain and are giving pain killers. Please help me to treat him. Thankyou,Navin Giri Shankhamul Kathmandu, Nepal