Neil Sedaka was one of America's most popular singer-songwriters, twice!As a boy growing up in Brooklyn, his talent was hard to miss. "I was a child prodigy," he told "Sunday Morning" in 2020. "I started at nine years old. Got a scholarship to the prep school of Julliard."When he was 13, he met a kid in his apartment building named Howard Greenfield. He'd found his lyricist, and they quickly hit it big.When we met six years ago, Sedaka told me about the song that made him a star, "Oh, Carol," inspired by his relationship with high school classmate Carole King: "I did date Carole King for about two minutes," he laughed. "Yes.…