Wow, that’s a lot of posts. This doesn’t sound like herpes to me but I can’t promise anything here.
Herpes causes constipation in some people with a new infection, not diarrhea. And he’s had no sores which is very important in all of this.
The CDC says never to do an IgM test – Mayo Clinic even stopped offering it as an optional test. It has no relevance here.
I hope someone will evaluate his prostate and see if that might be causing the issues here.