The Other Sister (1999)

Synopsis
Twenty-two year old Carla Tate (Juliette Lewis) is a slightly mentally challenged young woman who has spent several years at a sheltered private boarding school. Now she's coming home to her wealthy parents in northern California who are emotionally ill-equipped to deal with her and are guilt ridden over sending her away in the first place. The biggest limitation Carla must now overcome is her overprotective mother Elizabeth (Diane Keaton). When she takes a class at a trade school, Carla soon meets the equally challenged Daniel (Giovanni Ribisi). Despite his limitations, he maintains a job in a bakery and lives alone. Carla dares to dream of independence and love despite her mother who refuses to view her as an adult. When Daniel fails his class, his father cuts off his funds. Facing a move to Florida to live with his mother, the two turn to each other and find a way to stay together to face a world of adult opportunities and responsibilities. ~ Ron Wells, All Movie Guide