Atticus Finch's parenting style reflects his character, which is honest, trustworthy, and of the highest character and integrity. As Miss Maudie tells Scout, "Atticus Finch is the same in his house as he is on the public streets," meaning he doesn't ever do or say anything he wouldn't stand up to in front of anyone. When Atticus is talking to Scout about why he felt he must defend Tom Robinson, he tells her he couldn't live with himself if he didn't, that it was a matter of conscience, and that if he didn't defend Robinson, he more or less couldn't make Jem and Scout mind him again. At the novel's end, before Atticus realizes that it was Boo Radley that killed Ewell, he thought it was Jem and was determined that it would not be a cover-up.
Bob Ewell is an alcoholic, abusive "father" who drinks away the family's wages, hunts when its illegal to do so, does not require his children to go to school, beats up Mayella when he sees her with Tom Robinson, and it is implied that he sexually abuses her as well. The kids live at the edge of the garbage dump in a house that barely stands with a tin roof and the only time Maycomb acknowledges the family is when a Christmas basket is delivered.