Frequent urge to Urinate for 2 years.

My Father had been diagnosed with Urethral stricture as he used to urinate over 4 times an hour with severe irritation..and the problem intensified during night.He had undergone urethrotomy twice and dilatation in hospital over 5 times,and has been doing Self Catheterization for the past 1 year,but even after all this,symptoms never subsided.Within this 2 years he was affected by ESBl twice (klebsiella pneumonia) and (E.coli) and took medications for that and For the past 2 years he has frequently been diagnosed with UTI and taking medications for that.Still he cant sleep continuously for 1 hour undisturbed and cannot travel long distances by road.Now he had undergone Bladder Cystoscopy but Doctor told that there was severe bleeding during Insertion so he could not proceed further.But after seeing symptoms he is now administered Anti-Tb drugs,which he is taking for 3 months,Still there is no improvement.So please tell me what could be the problem,How to Diagnose it Correctly? Thank you