I suggest he fill out the following, which may give him some perspective:
Probability of dying from prostate cancer vs other causes if left untreatedA lot depends on his "physiological age" not just his "chronological age." It mostly depends upon what he prefers to do.
"Watchful Waiting" means there is no intention to treat it, just to have palliative treatments, like hormone therapy or spot radiation to bones, if symptoms (like pain) develop.
Another option is starting on hormone therapy right away. A 92-year-old man in my support group takes one 50-mg Casodex pill every day. He has some hot flashes, which for him are manageable. His PSA is low and steady. A stronger kind of hormone therapy include chemical castration (shots every 4-6 months). I don't know if orchiectomy is feasible without full anesthesia.
Another option is treatment with SBRT (5 external beam radiation treatments). An 80-y.o. man in my support group opted for this. He's had no symptoms of treatment. He proudly tells us that his erectile function remains excellent. He had the typical irritative urinary and rectal symptoms that went away after a couple of weeks. Of course, that's just one man. Others may be troubled with those symptoms for longer. There is little to no fatigue associated with these short treatment regimens. In general, older men recover more slowly from radiation.