Mr Hornby was the brother of Olive Hornby. Moaning Myrtle showed up uninvited at his wedding because she was haunting Olive, his sister, and apparently made a scene to remind Olive of the bullying she put up with when she was still alive. It was so big of a mess that Olive had to get help from the Ministry of Magic in getting rid of the ghost.
Mr Hornby was the brother of Olive Hornby. Moaning Myrtle showed up uninvited at his wedding because she was haunting Olive, his sister, and apparently made a scene to remind Olive of the bullying she put up with when she was still alive. It was so big of a mess that Olive had to get help from the Ministry of Magic in getting rid of the ghost.