Let's cleanly kill of their parents in the prologue. They don't have names or personalities and they only have about 5 lines altogether, but it's vaguely sad that their kids don't have them around.
So we've been developing this beloved character for a whole movie, a few short movies, two seasons of a television series and another whole movie, focusing heavily on their newly established bond with their son. Let's kill them suddenly, onscreen, with their son's possessed best friend who's trying to kill said son, in front of their own best friend and wife they just reunited with after 20 years. Our main protagonist then weeps over his dead body.