What irony can be found in Sydney Barringer's death as recounted by the narrator in the film, Magnolia?

At a 1961 awards dinner, Donald Harper told a bizarre story about how Sydney Barringer's unsuccessful suicide became a successful homicide in March, 1958. The suicide was confirmed by a note Sydney put in his pocket before jumping off a nine-story building where he lived. Three stories down, his parents begin to argue as usual. They often threatened one another with a shotgun. The shotgun unexpectedly went off just as Sydney was falling past the window. Apparently, Sydney had loaded the gun a few days before, and when he passed the window, the bullet hit him. Sydney fell onto a safety net that had been installed three days before. Had he not been killed by the bullet, Sydney's life would have been saved and his suicide attempt unsuccessful. His mother, who fired the shot, was charged with her son's murder, and Sydney was noted as an accomplice in his own death.