Stop reading everything!😉
So far, all you know is that your dad has an increased PSA. It's not even high, certainly not high enough to assume it (if it exists) has spread.
Be patient, wait until the biopsies are complete, then the consultant will clearly tell you the state of play, and the options available to you.
He may just say "lets do nothing", and keep a watch on it. Or he might say "Have these pills and injections, they will stop it growing". Or he might say "you can have surgery or radiotherapy" etc etc. All of which should give you optimism.
There's only one certain thing about trying to predict the future (we all do it) is that you will be wrong.
Just be optimistic and supportive to your Dad, while his story unfolds.
I guess that when we first get a clue that the mischievous little cancer has chosen us, we all start thinking about making a will, how will my wife survive without me, or even .will I see another Xmas.
In reality, the vast majority of us survive for many years, living out our normal life span. I hate the saying (but it's true) many more men die with prostate cancer than because of it.
Stop imagining, and go and give your Dad a hug😀