I am a similar age to you and three weeks ago I too found out my Dad (early 50's) has advance prostate cancer. This was extremely scary at first and totally consumes your mind (it still does now)!
It would be good to understand your Dads PSA & Gleason Score?
In the last three weeks, we have learnt a little more about this terrible disease and we have definitely found this forum a great tool to research/relate to similar stories/diagnosis. It definitely gives you more hope.
I am still a newbie to this world, but my advice at present would be to stay positive and try not to over think different scenarios even though I know it is hard. Take some time from work if you can, go on plenty of walks and talk about your feelings (this helped me deal with the original diagnosis and I feel much more positive three weeks later). This will help you be as strong as possible for your Dad and family.
There are also lots of other members on this forum with advance PC who still live full and happy lives many years on! PC is slow growing (even if it is the "aggressive" type).
I hope this helps to find some comfort.