How does Aunt Alexandra react to her brother's defeat in Chapter 22 of Lee's To Kill a Mockingbird? What does it show the reader about her?
First, Aunt Alexandra waits up for Atticus and the children to return home from the courthouse. Since the verdict is announced after 11:00 p.m., this act demonstrates that she cares for her family's safe return. Then, Aunt Alexandra's first sentence is to Atticus when the family walks into the house. "I'm sorry, brother," she says. Scout adds that she hasn't ever heard her aunt call him "brother" before, so this shows Scout that Aunt Alexandra does have compassion in her heart for her brother.
Aunt Alexandra's next concern is for Jem, which is understandable because he must look quite wrangled since he cried during the walk home. Aunt Alexandra asks, "Is he all right?" Atticus says that everything was "a little too strong" for Jem. After hearing this, Aunt Alexandra returns to her criticizing ways by saying, "I didn't think it wise in the first place to let them--" (212).
Atticus cuts his sister off as soon as she starts to criticize the situation because everyone is exhausted. What the reader learns, though, is that Aunt Alexandra is opinionated and sharing it is how she shows that she cares. For example, as Aunt Alexandra protests about the children viewing the trial, she indicates that she has the best in mind for the children's welfare, not just for herself. By noticing Jem's frazzled state, Alexandra proves that she does notice the children when they are upset or hurt. This demonstration of compassion seems almost out of character for Aunt Alexandra because she usually worries about teaching the children proper etiquette.
Finally, Aunt Alexandra assumes that Atticus has become bitter over the course of the trial. Atticus reassures her that he isn't bitter, just tired. Her concern for the impact that the trial has had on Atticus and the children goes far beyond her usual petty grievances. As a family member who is not the children's biological mother, Aunt Alexandra proves that she at does care about their wellbeing.
Aunt Alexandra’s reaction to Atticus’s defeat shows that, far from being unfeeling and rigid, she actually has a deep respect for her brother’s principles and is capable of deep empathy. When she calls Atticus “brother,” we get a glimpse into her character that is new and different from the stiff woman who constantly fusses over Scout. Aunt Alexandra's concern for Jem (she questions whether it was the right thing for Jem to attend the trial) shows she cares for the children, not just maintaining appearances. In fact, the conversation she has with Atticus at this point—
“This is their home, sister,” said Atticus. “We’ve made it this way for them, they might as well learn to cope with it.”
“But they don’t have to go to the courthouse and wallow in it—”
“It’s just as much Maycomb County as missionary teas.”
—suggests Alexandra's concern with appearance might have a deeper motivation than simple snobbery. If the “real” Maycomb County is the way Atticus says it is, then it seems reasonable to understand her protective treatment of the children is an expression of genuine affection.
Atticus' defeat gives us all an opportunity to understand Alexandra as more than the strict aunt who is absorbed with her family's social standing and with Scout growing up to be a proper lady. She shows empathy, compassion, and respect for her brother; in fact, she calls him "brother," something she doesn't do often. She shows concern for Jem's worry and sorrow over the defeat, asking if he is alright. Later, at the tea party with her mission group, Alexandra, we learn seems to see through their hypocrisy every bit as much as the narrator, Scout.