W,
Welcome out of "lurker" status. It sounds like your husband falls into that group where surgery really does tell us something we didn't expect to learn. I'm in that club as well.
James C did a good job in summarizing things. I am a G9 (4+5) guy who did surgery, then adjuvant IGRT.
Some elaboration on my experience -
I don't know what to expect as to long term side effects. I am just at 2 years out from RT, and have a couple that are RT-related. First, I have radiation cystitis, which is basically burns in the urethra that will not heal. It is annoying and sometimes scary to pass blood clots, but does not change any urinary issues beyond what I had from surgery. Second, I was already afflicted with some colo-rectal issues due to past surgeries. The RT irritated the scar tissue, and I have an increased bowel frequency as a result.
I still have some fatigue, but it is manageable.
Would I chose the same route again based on what I know now? Yes. What studies I have seen since (I was not on HW before treatment) expect my situation to be improved by the immediate RT.
I have a currently rising PSA, so there is still cancer out there, but I prefer to believe that there is less now than there was before.
I would have started the RT daily water routine earlier so that my bladder would have some time to get used to it.
How long will I live? Who knows. My GP has me getting a lot of exercise. He says that if I want a chance to die of PCa, I need to be sure and not die of a heart attack first.
Diet during RT - my RO simply said keep doing things the same - nothing extra or exotic (food or drink) from Sunday night to Friday morning. Keeping the diet the same supposedly helps my bowels stay on a predictable track.
Meds & supplements - they asked about everything, prescribed or not, even eye drops, skin creams, and over the counter meds. They took me off of supplements, and I did have to adjust some medication.
For the day to day, there is a link in my signature to my RT journey thread.
And to restate - each of us has a unique path, and we are not doctors, so we can only tell our story.
Welcome again