Try not to worry LR. Not easy I know, but until he has the biopsy results decisions can't be made about treatment.
There will be many on here with PSA lower, the same or higher than your dad's but the available treatments (and individual choices) may well be different, so it isn't a question of seeing how it was for somebody else.
How old is your dad, does he have other health issues?
When you say you are going to see the doctor on Monday, do you mean your GP or your consultant?
Either way, it's a good idea that you are going with him as two pairs of ears will take in the information better than a man who is being given unpleasant news.
No point in panicking at this stage. As Barry says, if the cancer is the "suitable" kind he may not even have to make a decision about treatment just yet. My husband's PSA went up to 6.5 before he chose a treatment and had a year on the Active Surveillance beforehand.
Get the Toolkit from publications so that you will at least have an idea of what questions to ask on Monday. Please though, don't get hooked up on the possibilities of what might be just by reading the information. A lot of it may well not be relevant to your dad
Best Wishes
Sandra