Hi Brian,
I do understand your concerns abacus your brother's health, but there has to be a point where you can allow yourself the option to stop fretting, even if you do not actually stop fretting? And that point may be where you have all that it is in your power to do. So, making brother aware, informing brother of potential consequences should the matter be as serious as you consider it maybe, and your's and your family's worries for brother.
From then on you and your family may have to set the worry to one side, acknowledge it, and accept that you can do no more about it? It is parked.
I too doubt that it is a symptom of PCa, but only from my limited knowledge and, thankfully even more limited experience.
Hope you all had a good weekend?
dave