Why isn't he under the care of a physician if he has other health issues? And aren't you allowed to speak to his urologist without seeing him?
Anyway, if your Dad is urinating large amounts frequently, he could have diabetes. You can't let that go. If he is urinating small amounts frequently, it could be a prostate problem and any number of bladder problems including a urine infection which can't be ignored. Your first step is to see his regular doctor. The results of that visit can determine if the urologist needs to be involved.
-Warren
TaG3 + CIS 12/2000. TURB + Mitomycin C (No BCG)
Urethral stricture, urethroplasty 10/2009
CIS 11/2010 treated with BCG. CIS 5/2012 treated with BCG/interferon
T1G3 1/2013. Radical Cystectomy 3/5/2013, No invasive cancer. CIS in right ureter.
Incontinent. AUS implant 2/2014. AUS explant 5/2014
Pediatrician