Talk to Rheumatologist on Mainly Hip And Knee Joint Pain With Generalized Body Aches

My grandfather is an 82-year-old male with no history of diabetes, hypertension, ischemic heart disease, asthma, or tuberculosis. He developed severe osteoarthritis about 4 years ago, mainly involving the hips and knees. An orthopedic surgeon advised hip and knee replacement surgery, but he could not afford the procedure and was also reluctant because of concerns about postoperative complications.He was prescribed analgesics and, for almost 2 years, took diclofenac sodium/potassium (2 tablets in the morning and 2 tablets in the evening daily). During severe pain episodes, he also received diclofenac and dexamethasone injections intermittently.After I completed my house job and reviewed his medications, I was concerned about NSAID overuse and possible renal injury, so I discontinued NSAIDs and arranged baseline investigations. USG KUB with PRV showed a left staghorn renal calculus without obstruction or hydronephrosis, a normal right kidney, and an enlarged prostate. He has no flank pain, fever, or recurrent UTIs. His serum creatinine is 1.5 mg/dL, eGFR 44.2 mL/min/1.73 m², and urine ACR 48.1 mg/g (microalbuminuria). Other baseline investigations were within normal limits. The urologist recommended conservative management, as the stone is asymptomatic and the patient does not wish to undergo surgery. He was started on Tamsulin Plus for BPH.Currently, his main problem is persistent chronic hip and knee pain with generalized body aches, requiring a walking stick for ambulation. His BMI is 29 kg/m². His current medications include paracetamol (2 tablets during the day), Tonoflex-P (1 tablet in the evening), and Tamsulin Plus at bedtime. He also uses topical diclofenac gel, massage, heat therapy, and a massager machine. During severe pain episodes, he occasionally receives half-dose tramadol injection because of his reduced renal function.As we live in Alipur, a rural area far from major cities, frequent clinic visits are difficult. What medicine should be added?