Hello benbillbob3 and welcome to the site.
I'm so sorry that your dad is having to cope with his prostate cancer at 82.
It's a difficult one,isn't it, because at 82 he would likely have slowed down anyway but is pushing himself to try and keep fit because of the effects of his treatments.
I cannot answer your questions and fears but I hope that somebody else with the necessary knowledge will be along to advise you.
Failing that, tomorrow you could ring one of the nurses on this site who are apparently very helpful.
We can't control the winds - but we can adjust our sails
I’m 60 and was diagnosed back in May with PCa widespread through the bones. I’m also on hormone treatment and my oncologist has said that it makes the cancer wither away because it has nothing to feed on. It kills say 98% of the cancer and the other 2% goes dormant but eventually finds a way round the hormone therapy and comes back and then they hav3 to hit it with something else. Eventually they will run out of something else’s. from a positive viewpoint I understand that there are lots of new treatments in development
You need to find out what the current situation is.
From what you say, it seems that the hormone therapy is not fully effective.
It may be that further treatment (cytotoxic chemotherapy) is possible, but at 82 and already frail that may not be an option. It may be that you should get a referral to hospice care (they take people on long before the end is near), as they are almost certainly the best people to advise on symptom control, and when he does need their full care, he'll be familiar with them, and they with him.
-- Andrew --
"I intend to live forever, or die trying" - Groucho Marx