You could tell her to look up the special carbohydrate diet. It is a diet that completely changes the gut flora and helps healing inflammation in the gut. So far not much school medicine research was done, but a preliminary study with 11 subjects with crohns, 9 got better and all 11 felt better after some time on this diet. Anecdotal it helps a lot of people with crohns, IBS, SIBO, GERD and even some with parasites.
It doesnt matter what she might have, but if GPs have given up to look for a solution, she has not much to loose to try this out.
It is however important that she starts the diet with the intro diet part first, and then she has to tweak it so she feels comfortable with it. No need to eat pumpkin if you hate it, right?
Good luck!
Welcome to the gastroenterology community! It is hard to recommend what your friend should do without knowing all of the tests she has had.