Rosie!

Rosie is a 1967 comedy film directed by David Lowell Rich, based on Ruth Gordons play A Very Rich Woman.

Daphne rushes to Olivers office, but runs into his much younger associate David Wheelwright Farentino, who promises to help her after an emotional conversation. Oliver is upset to find out that one of his workers is taking matters in own hands, and meets with David to hear him out. David advises that they should put someone with Rosie to prevent her from doing anything outrageous, because their daughters are sending a private investigator to the case. Oliver takes his advice, but sends him on the job. David reluctantly starts the job, but is quickly drawn to Rosies extraverted personality. Simultaneously, he goes on a few romantic dates with Daphne and they fall in love.After attending a piano recital, Rosie is abducted by two men, and later awakens in a locked rest home for the mentally unstable in the Santa Monica mountains. Rosie is heartbroken to learn that her daughters committed her to a sanitarium, and rejects an offer from Cabot to sign the papers for her release in exchange for making them responsible of her finances. He assures her that they can keep her in the sanitarium indefinitely if she does not obey their wishes, prompting Rosie to reconsider. Meanwhile, Daphne finds out what has happened, and furiously leaves the home, despite her mothers plea not to leave her. ........

Source: Wikipedia