One of Holly's last songs, Love's made a Fool of You", recorded in 1958, sounds a lot like the early Beatles. But at the time of his death in early 1959, Holly was experimenting with unusual [for 1959 rock] musical directions. He was planning an album of "Ray Charles sound" music as well as an album of gospel music. He was also studying jazz, as well as cajun and flamenco guitar styles, according to "Remembering Buddy", by John Goldrosen and John Becher, 1986.
Had Buddy Holly lived, he most likely would have continued to grow, both influencing, and being influenced by, other groups. He might even have collaborated with the Beatles. There's no way of telling just what he might have developed into. Goldrosen and Becher say: "If the Beatles had died in 1964, would the same evaluation [that they "died at their peak"] have been made? Probably, because what they did afterwards was unpredictable." Holly was only 22 when he died in 1959.
