Harper Lee's depiction of the family in the deep South of the United States is certainly a realistic one, although in some ways the Finch family is not typical, especially with Atticus's leniency in how the children address him and in his liberal attitudes about many things. Yet, the importance of family loyalty is one trait that is greatly stressed in Southern families and the Finches clearly exemplify this attribute. Even when she does not agree with her brother's action of defending Tom Robinson, for instance, Aunt Alexandra will hear no disparagement of him. For, she is grateful when Miss Maudie cuts short the innuendos against Atticus by Mrs. Merriweather who attends the missionary tea. Likewise, Scout and Jem's loyal actions of speaking up for their father at the jailhouse and when Atticus is in the front lawn with many men demonstrate the strong family ties that they have. The fondness for their maid Calpurnia, who acts as a surrogate mother to Jem and Scout is very credible, especially since the mother has died. And, that she would scold and spank Scout is also within the realm of the norm for Southern families of the time of the setting.
Also, in the families such as the Finches, pride in their lineage is not untypical. Aunt Alexandra's insistence upon Scout's wearing dresses and adhering to certain standards of behavior is consistent with the area and type of family in which the Finches live, as well. Again, it is Atticus's more nonchalant attitude that is not typical.
In her depiction of families, Harper Lee, is certainly realistic in her illustration of the Cunninghams and even the Ewell family, too. The poor, but honest Mr. Cunningham and his son Walter illustrate well the many American families that suffered during the Great Depression. The dysfunctional Ewells who live by the garbage dump typlify the poor white trash family of the deep South. These are probably the despicable progeny of the indentured servants and criminals who were sent or migrated from the British Isles to such places as Georgia's penal colony and its neighbor state, Alabama.