Commas Surrounding "And"

First, look at the sentence with all of the parenthetical information removed:

Scout's father is hired to defend Tom in the trial, and Atticus takes the job seriously and does his best.

Now add back in the parenthetical information—but use actual parentheses (I have also emphasized the text):

Scout's father (Atticus) is hired to defend Tom in the trial, and (although it is a lost cause because of the racism of the people of Maycomb) Atticus takes the job seriously and does his best.

Finally, replace the parentheses with commas:

Scout's father, Atticus, is hired to defend Tom in the trial, and, although it is a lost cause because of the racism of the people of Maycomb, Atticus takes the job seriously and does his best.

As you can see, there is always a comma after trial. It's not that the and after it is in a pair of parenthetical commas, but that the entire although . . . Maycomb phrase is in a pair of parenthetical commas.

In short, there's nothing wrong with the use of the commas in the sentence.