Prayers for your mom. My ex had a surgery for that same exact problem. It was a tough surgery. Mostly she will need to rest and eat well. With diverticulitis if you eat small seeds or popcorn or nuts, it gets stuck in your gut and causes inflammation and infection. It is curable with surgery though, and she may feel better after she heals. My ex felt 1000 times better. He begged for them to do the surgery because his bowels were so inflamed. Just wanted to let you know my experience with this condition.
Praying for your mom.