How did you get your diagnosis?

Hi there! I'd like some advice of diagnosed people here, because my partner and I are running into a dead end with his stomach. A bit of back story to make it make sense.

My partner is early 30's and recently diagnosed with hEDS. When I met him, he was so skinny. Like, malnourished skinny. He's 6ft10/200cm but weighed just above 80KG. He's always exhausted, always nauseous, always terrible diarrhea. Since we're sharing a house hold, we've tried loads of things: FODMAP, gluten free, small portions, big portions, eating through-out the day consistently in small amounts, b12 injections, pouches for better bowel movement, magnesium in different types, more sleep, less sleep, and it's barely doing anything. He has managed to get to a healthier weight in which his cheeks look fuller and healthier and there's a tiny bit of fat to not make bones as visible to the eye. But. We're stuck. There's no progress. Some EDS patients in the local community have feeding tubes because they have GP. I'm starting to wonder if he might have the same thing going on. Out doctor is usually quite open to suggestions, as long as we can build a good case/reason why we think of certain ideas.

What was your story of symptoms/events that lead to a diagnosis? And do you think this could be a case that might be worth mentioning to the doctor for diagnosis consideration?