When Dick Grayson dies they do not bury him with his parents in Gotham Cemetery. They bury him by the side of Bruce Wayne in the Wayne family's private cemetery, at the edge of Wayne Manor's grounds.
They lay him to rest on Bruce's right side, why should they not?
He was the perfect son who always stayed by their fathers side. He was the first of them and the best of them. He had always been Bruce's right hand, so they buried him accordantly.
Dick Grayson's remains rest by the side of Bruce Wayne, where he lived his life. Almost like the Egyptians would bury their dead with their most precious items, like the vikings would bury their leaders with their most loyal slave, like a dog Dick Grayson are left to guard the site of his master's last resting place.
Dick Grayson always leaves but he always comes back too.