Suggest Treatment For Knee Arthritis On Right Leg

Dear doctor,My mother has knee artrhrosis on the right leg and Parkinson's disease an advanced form. She has great pain in the night.painkillers don' t help her any more. What can I do for helping her,? She hasn' t a good condition for a surgical intervention.she is in old woman 75 age, Medical history:HTA ,osteopenia,peptic ulcer,