Do you have any suggestions for clic movies to buy for my parents?

My sister is a geriatric nurse and she tells me that her patients love old movies, especially musicals. She is often impressed with the folks who have impaired memories who sing along with Judy Garland, Frank Sinatra, Debbie Reynolds and other stars of musical comedies. They know all the words! Some of the movies she recommends are "Seven Brides for Seven Brothers" and "Holiday Inn" and "Singing in the Rain."