Hi M
I am also T4n1ma although my spread is to the lymphs in my body at this stage.
I was diagnosed 21 months ago, have had chemo, RT, zoladex, biclutamide and now Abirateone. Life has been ok, I am 51 opposed to in my 60s like your dad however am still running marathons and beyond.
My prognosis was a range of dates but I decided after the initial emotion that I would do my best to enjoy life and only worry about things when they happen ( easy to say I know). I totally understand your desire for a time but as others have said we are all different.
My PSA went from 342 on diagnosis to 0.3 now under treatment so the cancer is less advanced now than it was on diagnosis , I know it's waiting to reappear but those numbers show that treatment can work.
I would respectfully suggest that your dad asks about the treatments I have had and see what his onco says about why or why not and when ( for example abiriterone will only be used after zoladex/pristap fails however research shows that all things being equal early chemo I'd now, may extend ones prognosis).
Keep posting your thoughts or any questions here.
For me my diagnosis has made me feel it's a time to start living not the other.
Kev