I also had blood and "crud" on the catheter tube.
My nurses said don't use anything petroleum based on the tube, but many here on the board seem to have had good luck with Neosporin (that is what my dermatologist advises for everything).
I just cleaned often, maybe 5 - 6 times a day.
I used the big/night bag all the time, after getting dire scare warnings from the nurses about infections.
Don't let him strain. Use either a gentle stool softener or some mineral oil if things don't move. I use Docusate Calcium 240mg, which is not the most common - you might have to ask at the pharmacy counter.
Get some hand sanitizer for the family, and put a bottle at the door to the family room and the bedrooms - treat the house just like the hospital room. Use it each time passing the door. I use that at home, and have it at the entrance to my office area - nobody gets by without using it (I'm still seriously immuno-supressed from the IGRT). It is rough on the skin, but does the job.
Have lots of tissues, and bag the trash often - smaller bags work better, as you'll tie them up and "seal off" the germs more often. Wash the general hand towels more often.