Short Bowel Syndrome

I am seeking help for someone who has had about 5 feet of her lower large intestine removed and some of her colon.
Her symptoms are very much like irritable bowel sysndrom with constant diarrhea. The bowel was removed due to severe diverticulosis. We understand that the diarrhea is not curable due to the part of the gut that was removed. She does not reabsorbe water and form stool correctly.

She is malnourished and weighs under 100 pounds. Very thin. She does not eat any sugar but tolerates fats well. She cannot eat fruit. She receives monthly B12 injections.
She does not tolerate fiber as it makes the diarrhea worse.

We are trying to find ways to utilize vitamins topically.,
any information of topical administrations of vitamins would be appreciated or any other speciality preparations that are sublingual.

IV administration is not practical as she lives 100 miles from anyone who could do it.
Thanks
Arrow