I agree that approaching your father is the best course of action.
I am the opposite of some of the men here, in that I can discuss my medical issues without it bothering me. My mother had a nursing background, so maybe her frankness in discussing medical things when I was a child led to me being able to discuss things without embarrassment or anguish now.
Every patient's situation is different, so anything that might be posted here about what might be going on medically with your father would be speculation. As others have suggested, sit down with your father and quietly ask for information.
Good luck to you and your dad.
Nerve-sparing, open prostate surgery November 13, 2007
Gleason score 9, PSA 14
Biopsy result - 9 of 12 sticks showed cancer
Despite high Gleason score, cancer was confined to the prostate
Possible post-surgery radiation therapy...decision likely in late April 2008, depending upon PSA at that time
Unrelated surgery January 2008 delayed incontinence recovery, which is now showing good signs of improvement (fraction of a pad a day as of March 2008)
Began using Viagra 3 times a week December 2007 to stimulate blood flow
Began using Osbon Erec-Aid Esteem manual pump for therapy mid-February 2008
Will probably begin using bimix injections in addition to Viagra and pump in May 2008