My Mother, Age 93, Has Diverticulitis. Since October She Has

My mother, age 93, has diverticulitis. Since October she has been through 2 10-day rounds of antibiotic pills, 3 days in hospital with IV antibiotics followed by 7 more days of antibiotic pills. She is still experiencing periodic lower left abdominal discomfort. Her doctor told her to eat bland, low fiber diet. He wants to avoid surgery because of her age. Is low fiber actually correct? Should she stay on a liquid diet? She was only on liquid diet for 2 days.