Hi SR12, I've been keeping an eye on the posts as usual, I just haven't responded to most on this thread as I don't have enough experience of all these health issues.
I can tell you the PSA is nothing to worry about. His hospital is testing to two decimal places mine tests to one. My last three all six months apart have been <0.1, 0.2, 0.1 so mine are roughly 5 to 10 times higher than your dad's, and mine would have to be 10 times higher than they are to be of any concern.
Remember he still has a prostate and if it is making PSA as great as 2.0 it will not be considered a problem.
I'm sorry about your dad's other health issues. You may remember one of my first posts on this thread was the recommendation to take up motorcycling or sky diving. Your dad's problems are all to so with getting old, and there is no cure for that, yet.
I think your dad's case does highlight a decision people can make about treatment, and before I say anymore I should point out this decision still has no right or wrong answer.
If your dad had have opted for no treatment, he would probably have got most of these subsequent problems anyway, but he would have almost certainly attributed them to advancing cancer even though they are not. He would have been spared a few minor side effects of treatment. He would probably have got voiding problems which would have been genuine cancer problems. He may have died an unpleasant death from cancer at about 85.
By opting for treatment he has got the subsequent problems, but they are almost certainly not related to cancer or side effects of treatment (save for a few like hot flushes). He now is worried the problems are either advancing cancer (which they aren't) or side effects (which they aren't) he probably will not develop voiding problems or die an unpleasant death at 85 from cancer, he probably will die an unpleasant death (they always are) at 85 of something else.
So certainly no right answer or wrong answer to the treatment question, for someone diagnosed with a slow cancer in their late 70s.