Definitely not. The Bye Bye Man is purely fictional. Horror movies like this typically draw from the imagination of the writers and directors to scare and thrill the audience, not from real-life events.
The Bye Bye Man isn't based on any true events. It's a product of imagination and creative writing in the horror genre. Don't expect to find any real facts behind it.
I'm not entirely sure. It could be either. There are many works, both in literature and cinema, that are based on true stories. It might be a book that chronicles real - life events related to leaving Germany, or it could be a movie that dramatizes such a story.