Suggest Treatment For Diverticulitis

My daughter Bianca 32 has diverticulitis, her father died of colon cancer at 62. She has had pal-ups removed in a colonoscopy. I feel as her mother part to blame as she did not receive the same nutritional regimen her older sister had, as I had become slack in nutritious whole foods in providing for her. How can I help her? She is a family therapist, engaged, in hopes to have a family of her own.