Hi welcome to HCM. A diverticulum is a tubular extension in the intestines and your mother has it in her duodenum
. Sometimes food particles get impacted inside it and it gets inflamed. This can lead to the kind of problems she has. A course of anti inflammatory drugs and antibiotics will temporarily give relief but the episodes can recur. I am afraid surgery is the only cure. But of course, before that she must preferably undergo a gastro duodenoscopy to rule out other causes of abdominal pain
and occult blood in stools.