Thanks for posting your query.
Your father has significant disease of prostate
and the pain suggests that he may be suffering from prostatis as well. His prostate is enlarged and is the cause of obstructive uropathy
and is causing changes in the kidney
and would lead to rapid derangement of kidneys if left untreated.
You should get a urologist
consultation and send the prostatc secretions for gram stain and culture.
If organism is detected then treat with antibiotics which would be helpful in great way but ultimately the surgery may be the only good solution.
might be not related to your current problem but a silent accompaniment.
I will be available for your follow up queries.