If Barrett dies, Sam Coe and Cora will still constantly have the dialogue about going to tell him a joke. It doesn't make sense since he's dead.
There is a radiant line between Sam Coe and Cora, would need to someone flag it to not trigger if Barrett is dead.
Get far enough un the story and have Barrett die. Then fly around Grav jumping with Cora and San Coe aboard, they will have a radiant conversation about a joke she knows, Sam Coe will recommend she tell it ti barrett