I hope your Dad gets a good report,
I've had many kidney stones since I was 28, and thirty years later I see blood in my urine on a regular basis. I do notice more red tinges if I had an especially vigorous day of moving, such as spraying the underside of my car with a rust inhibitor, or doing maintenance on the cutting deck of the Kubota tractor at my part-time work. The stones move around, and blood is the sign of their movement. I see a urologist 1x per year regardless of any attacks.
Not saying this applies to your father, but a large percentage of men will have some stones at some point in their lives, many will pass with no pain and no evidence = no indications of KS problems.
Once again, hope all goes well.