Hi!
I want to first suggest that you post your comment to the Gastroenterology doctors, as they are really the proper experts to answer your questions--My specialty is womens' reproductive health!
It sounds to me as though your relative may have encountered some sort of parasite--possibly something like Giardia. I would want to run a battery of tests for ova and parasites as well as a stool culture. I would also want to test for blood and white cells in the feces.
If those tests were negative, I would suspect something like Crohn's or ulcerative colitis, or even Sprue or gluten sensitivity. Again, there are many tests for these--some blood tests, some feces tests and possibly even a colonoscopy or upper GI study.
Please re-post to the GI doctors, or if they are way to busy, you could start with general internal medicine doctors!
Good luck to you and him!
Dr B
Thanks For Quick response..