Although Victoria had spent enough time with humans to return back to humanity, Lily was gone for good. She considered Mama as her mother, and her happiness laid more with Mama than anyone else.
During his escape, they crash, find a cabin, and Jeff seems resigned to killing himself. However, he knows that will leave his daughters to suffer death by exposure, so he decides to kill them first. Mama lifts him up and breaks his neck before he has the chance.