Yes the PSA is for prostate cancer. There is some literature that suggests that those who have prior rectal ca are of incresed chance of prostate cancer, but if all you have had is a psa test they won't know that. There are many men who have a high PSA test and no cancer, so what is next is a biopsy of the prostate. From that you will know much more in terms of how high a score it is etc. For your father, given his age an option might be to do nothing and just monitor the situation. If you want some more info there are some good sites giving patient info on prostate cancer on the internet.
Hope this is of some help
Good luck with it all.