Molly (1999)

Molly McKay is a profoundly autistic twenty-something woman who has lived in an institution from a young age following her parents' death in a car accident. When the institution must close due budget cuts, Molly is left in the charge of her neurotypical, older brother, Buck McKay, an advertising executive and perennial bachelor. Molly, who verbalizes very little and is obsessed with lining up her shoes in neat rows, throws Buck's life into a tailspin as she runs off her nurses and barges into a meeting Buck's agency naked. When Buck consults Molly's (beautiful) neurologist, Susan Brookes, Dr. Brookes suggests an experimental surgery in which healthy brain cells are harvested from a donor and implanted into Molly's brain. While Buck initially balks at the suggestion, he finally consents to the surgery and Molly makes a miraculous "recovery" from her autism when she begins to speak fluidly and to interact with her brother, caretakers, and the world, in general. Buck begins taking Molly to social events, like a production of Romeo and Juliet, a baseball game, and expensive dinners. However, after a few months, Molly's brain begins to reject the transplanted cells and she begins to "digress" into her former, autistic state. Both Molly and Buck must accept the eventual loss of Molly's "cure" and her regression to her previous autistic state. While Buck initially rejects Molly and sends her to another institution, in the final scene of the film, Buck accepts Molly's autism and vows to remain in Molly's life by visiting her at the institution.