"so now does this sound like IBS? (Which I don't know that much about either--but also stress related?)"
"IBS" is nothing but a catch-all diagnosis when there isn't an official answer. You might want to look into rosemary - the herb could become his friend for several reasons.
"He probably wouldn't be one that we could convince to go have a stool sample done..but parasites/giardia/ecoli infections are a big possibility."
Stress can cause constipation and/or diarrhea problems. I do think the possibility might exist with a possible parasite problem (intestinal/bowel related changes), and also a liver problem. The liver is a very key organ and it does play a role with hemorrhoids, whether it shows up as "stress", constipation, or diarrhea. Any kind of bowel straining (constipation) or uncontrolled force (diarrhea) can trigger a problem, until he gets it under control.