The author must be a big fan of true crime cause this definitely reads like one of those stories: 17-year-old Makayla lives the perfect life until one night, just before her big birthday bash, she leaves home and is never heard from again...until 12 years later when they find her body under the gazebo and turns out the father did it and has been lying to everyone this whole time. You can practically see the nexpo video on it.
Really the biggest problem is the climax. The story spends so long building up the act, and for that all we get is a tense reunion before suddenly the narrator and the brother are running in the field while being shot at, and just as quickly the conflict resolves itself and the story's over. The dad's motivation makes no sense in the original story. So he's so worried about being found out about the original murder he's decided to kill his entire family (and himself, probably) then and there? You'd wish there was more beyond that.
The addition was a funny morbid twist. Really, if you tighten up the pacing you'll have a fun little joke story akin to Return to Sender.