I always understood that line to be referring to JFK, RFK, and MLK’s assassinations.
I thought the line about “the father, the son and the holy ghost” referred to the three entertainers who were killed in the plane crash. I am not certain which is which, although Jiles P. Richardson (the Big Bopper) could be the father because he was the only one of them who had kids, and Ritchie Valens could be the son because he was the youngest, which leaves Buddy Holly as the holy ghost.