I Took a Time Machine Back, Stopping My Granddaughter's Bar Trip

My granddaughter kindly went with her heartbroken best friend to a bar to cheer her up, and got stabbed twenty-five times. Her internal organs were badly damaged. She spent a month fighting for her life in the ICU, and for the rest of her life she'll have to wear a colostomy bag. My son and daughter-in-law furiously demanded an explanation, but my granddaughter's best friend just rolled her eyes. "She came with me because she wanted to. Nobody forced her. Don't tell me you people are trying to shake me down for money?"