After a visit to the urologist......tribulus is a good place to start. It helps the body of the male produce testosterone, and brings it up to natural levels. Start with the smallest dose, of course.
A stronger remedy is the Tongkat Ali, also known as " longjack" for obvious reasons....if the issue is inflammation, uva ursi is taken once a day to start, in the morning, with a full glass of water. This stuff can ease urine passage considerably, and will make him urinate copiously . Look up the info on these online, after making sure there is no obstruction. Good luck!