My 74 Yr Old Father Has Had Problems With Urinating.

My 74 yr old father has had problems with urinating. He has had a turp and has had his prostate checked and there is a small pc of tissue that could be removed but it isn't recommended. He post void residuals are about 100 cc. He has some burning in his penis everytime he voids and his stream has decreased this year. He has frequent UTI's that result in E-coli. He had a cystoscopy and CT to rule out fistula from diverticulitis and CT was normal and Cystogram was also. He developed a post procedure infection that required a murphy drip for the bleeding and iv antibiotics, they sent him home 3 days later and he is on antibiotics. He still has pain and difficulty voiding and now has swelling of one testicle. What would cause the swelling?