The Pardoner’s Tale by Geoffrey Chaucer is the story that Rowling chose to base the Deathly Hallows off of. The tale is one of many from the well-known book, The Canterbury Tales.
When Kingsley Shacklebolt was made the permanent head of the Minstery of Magic, he banned the use of Dementors to guard Azkaban, and everywhere else in the wizarding world.
What the Hogwarts headmaster really saw was his entire family alive and happy. He also saw his beloved sister Ariana alive and Aberforth forgiving him.