I sympathize with your father's anxiety about these potential aftereffects. I have been dealing with the same concerns for more than 7 years. I have not had surgery but it has been hanging over my head. My PSA is 12 or higher but repeated biopsies find no cancer.
My advice is to be sure to find the best surgeon in the USA. Your local urologist is not the person to entrust with this issue. Be sure that he has done hundreds, if not thousands of these operations. It requires the utmost skill and that only comes from vast experience. Consider places like Johns Hopkins in Baltimore or the Mayo Clinic or the Cleveland Clinic. These are places with the experience and therefore the cutting edge skills. It was Johns Hopkins where they learned the techniques of "nerve sparing" that avoids impotence, and which everyone now tries to use.
In addition to the other web sites which have been suggested to you, I would also recommend one which is unusual but in my experience very helpful. It is the Yahoo Group called "Prostate Cancer And Gay Men" . I'm sure the very name will set your father's teeth on edge, but there is no group of men more concerned with the issue of impotence/incontinence then this one. The biggest advantage of this group is that they are not embarrassed or awkward or shy about discussing the nitty-gritty of this issue or their experience in dealing with it. There is even a lot of wisdom there as to the impact on, and the role of, the caretakers like your mother and yourself. They are very welcoming to non-gays and there have been a number of wives and daughters who have sought advice there, although if your father does not find it repulsive it might be best if he asked his questions for himself as I did.
Best of luck to your father and your family, and remember your father's well being is worth every penny of the cost to travel to a medical center of excellence to have his surgery.