My Daughter Has Been Having Problems With Digestion Since She

My daughter has been having problems with digestion since she was a baby. At the age of 14 she had an ulcer. She is now 37 and has IBS. Is there something lacking in the stomach that deals with digestion. She has been seen many times by doctors with no real help for her problems. My other daughter has a similar problem. Their food does not digest in the stomach and was found in the stomach the next day.
Thank you for your help.