I guess you already realize there are no easy answers for your questions. Remember that PCa is a Twilight Zone of its own.
I am currently on an upward path of PSA after surgery & RT. Mine is up to .4 (from undetectable, <0.01, a month after RT finished, just about 15 months ago), and the uro has me scheduled for next test in December.
He has not set a starting point for HT, but as many posts you'll find on the board, there will be as many points. So I ask the same sort of questions. My uro is much more optimistic than I am, and wants to wait. Some on the board will say start yesterday, and have very valid reasons to say that.
So first question, the starting PSA depends on the doctor and patient. There is no standard number.
How many don't go refractory? I don't have any statistics at hand. From what I read, eventually they all could, but you might have to live far more years than any of us could even hope for to fall in that category.
How long does HT remain effective? It depends on the variety of PCa. Some here on the board have had very good results. Again, you'll have to search for statistics.
For the last question, you have to know your particular answers to all of the above, and avoid all the other risks in life. Your dad very well may (and I hope he does) respond positively and be done with PCa.
I tend to think all of these questions are valid for the conversation with Dr. Myers, but the only answers will be statistical.
Moderator - Prostate Cancer(Not a medical professional)
My adjuvant IGRT journey (2010) - www.healingwell.com/community/default.aspx?f=35&m=1756808