Local pressure and bruising can inflame anything.

We get swollen feet from tight shoes and bumps, lumps and swelling from impact injuries, so it stands to reason that the prostrate, or tissues surrounding it can get inflamed from too much time sitting on a saddle that doesn't fit right. This shouldn't surprise anybody, though your friend seems to have gotten a very extreme case.

Men over 50 may also have another reason to be careful about bruising or swelling. Many are on low dose aspirin, which is a blood "thinner". That makes bleed and swell more than when we were younger.

The same advice applies at any age, know and listen to your body. If you overwork your body, know what's changing and monitor that for effects. Doesn't mean running to the Doc for every little thing, just watching for implications.