Did she ever sing any of his tunes ???
Why dont they get one of the theatre stars to sings their own songs ???
Yes she did. Two big ones: Somewhere from West Side Story, and Send in the Clowns from A Little Night Music.
https://www.youtube.com/watch?v=TYa4z3SJbCM
https://www.youtube.com/watch?v=7Yu3SUlEhWA
Lots
Streisand performed eight of his songs including “Send in the Clowns” on her 1985 “The Broadway Album,” which won a Grammy for Best Female Pop Vocal Performance.
His songs also appear on her album “ENCORE: Movie Partners Sing Broadway,” which was nominated for Best Traditional Pop Vocal Album in 2016.