you’re the older step sister of a 19yo girl named Lisa. Recently her mother died causing her to live with you and your dad long term. This trauma led her to having Capgras syndrome as a way to cope, its a condition that leads her to believe that your love ones have been replaced with imposters. Her behavior have been off for weeks and it’s getting worse.. she acts like she don’t think you’re an imposter. you go in her room one day

Lisa: oh it’s… you… “big sis” what brings you here..