At the outset of this story, Dill describes his father as having a long black beard. When the children begin playing and describing someone with a beard, Dill recants his statement, lying again and saying that his father had shaved it off "last summer." He also says that his father allowed him to help the conductors of a famous railroad, and that he had been sent money by him. None of the above are true.
Dill's reasons for lying boil down to the issue of attention: He is not affectionately tended to in the same way the Finch children are, and therefore feels the need to invent or justify his family's actions. And while Dill may not be as well-parented as the Finches, he does have a way with persuasion and imagination; Dill is the instigator of most of the mischief experienced by Jem and Scout, in fact. He is a friend, cohort, and fellow conspirator in most situations.
Dill lies about his father and the rest of the family because he doesn't want anyone to know that he is not treated as well by his family as Atticus treats his children. He wants to be thought of as a "normal" child. Although he is not abused, he's ignored by his family and left to his own devices. Because of this, he's seen almost every horror movie and delights in telling the details to others. He adds imagination, color, and, at times, drama to Scout and Jem's lives. He is the one who often begins much of the mischief the children get into. He dares Jem to approach the Radley house and makes up the "Boo Radley" game. He even runs away one from his own house and is found under Scout's bed.In "To Kill a Mockingbird", Dill's antics serve as a welcome comic relief to the grim story surrounding Tom Robinson and Mayella Ewell.
Dill lies about his home life in order to feel better because he does not have a very good relationship with his parents. He feels bad and he is quite lonely. In order to feel better he lies and he runs away to Maycomb to be with Atticus and his family because those are the people who actually care for him.
Dill often lies about many things to make his life more exciting. He added to Jem and Scout's lifea childhood friendship with memories that would never leave.