Although Jem and Scout are being brought up in a one-parent household, they get far more attention from Atticus than Dill gets from both of his parents in To Kill a Mockingbird. Dill's parents ship him off to Maycomb each summer, presumably because they prefer to be without him for a few months each year. Atticus spends as much free time with his children as possible and advises them when he feels they are in need of it. Dill's mother apparently divorces her first husband because the boy speaks of his new father later in the book. Neither of them seem to have much inclination to spend time with him, however. Dill's parents lavish him with more gifts and monetary favors than Atticus, but Jem and Scout seem to sense that this is in return for their own lack of time and interest. Atticus gives his children a large degree of independence for kids so young; Dill also is given more freedom than most kids. However, Atticus does this in an effort for his children to learn things on their own terms, while Dill is forced to do so because of his parents' lack of hands-on participation.
The major thing that is similar between the two families is that both families love their kids. But there is a major difference.
Atticus Finch really wants to be around his kids and to do things with them and to let them participate in his life. He doesn't just kind of push them off to the side to do their own thing.
By contrast, Dill's father seems to not really have time to do much with Dill. So Dill is kind of lonely in a way that Scout would never need to be. I can't imagine Scout ever saying that she didn't have a father the way Dill says that he doesn't even though his father is still alive.