Hopefully your dad has started his treatment. I have just completed 4 weeks of RadioTherapy and fortunately had very few side-affects.
My initial PSA was 14.8 and now waiting for an appointment to see what it is now.
Most people at the clinic seemed to be coping well; even those who had daily treatment for up to 45 days. So I hope your dad has some positive results and will be in remission for several years.
My thoughts are also with you; as I started the cancer trail in 2014 with Kidney cancer (removal of right kidney); followed by secondary kidney cancer last year (removal of 2nd rib & tumour) - they spotted my prostate issues during bone scans.
Have to continue with 3month Hormone treatments and hope to get the all clear for another year or two, on both cancers by the end of November.
Good luck for the future.