I can answer this delicate question.
Guys should wash their dicks every day, especially if they are not cut. Personal hygiene classes covered this when I was in the military; the topic, keep the dick clean so it doesn't become infected and always use a condom. Guys that are cut have an easier time keeping the male member clean, but the medical staff pounded it into everyone that the male organ had to be kept clean: no excuses, if you got a dick infection you could wind up in the brig!
It is also descried as the prepuce, a technically broader term that also includes the clitoral hood in women, to which the forskin is embryonically one and the same. (The dick in men has the same development path in the embryo as the clit in women and to has similar nerve ending and the same sexual satisfaction as in men.) So, if the clit is covered, the women were told to wash there too. A dirty clit, and infections, could also put them in the brig. All of the privates, both men and women, were instructed to wash their privates.
In the 60' every lady I visited washed every dick with soap and hot water. I don't think I have seen anyone in the last 20 years that did. So, I always shower before, and after, any visit. If a guy can't wash after a visit he can always get some whiskey, 70% rubbing alcohol is better, and dip the dong to help kill any germs.
You are telling us the he had so much crud under the foreskin that it made the condom come off.
Really now, the guy is disgusting. Get a pan of hot water, soap and a wash cloth and wash the damn thing for him, if he is that stupid. Protect yourself.
Sorry you had such a negative experience.
JR