Hi!
I think your father should be around 50.
You might need to see an Orthopaedic surgeon for all these complaints. He needs clinical evaluation and may be a few investigations like X ray for better assessment of his pathology.
Next Steps
Might try a short course of NSAIDs and local application of gel to relieve pain
Health Tips
Dont use NSAIDs if he is having
kidney disease and/or
Diabetes.
At this age, you better consult an Orthopedic surgeon directly ( may do so via Practo), so that his quality of life is not deteriorated further.