What ideas at the end of the chapter 11 does the author want to emphasize?

The most important idea conveyed in this chapter is the true meaning of courage. Scout and Jem are regularly subjected to vicious tongue-lashings by Mrs. Dubose, a mean old lady who lives in the neighborhood. It's bad enough when she starts yelling at the children about running wild, or accuses them of playing hooky, but it's even worse when she trash-talks Atticus about representing Tom Robinson in court. Jem always tries really hard to stay calm in the face of Mrs. Dubose's abuse, but the insult against Atticus is just too much, and one day he snaps and goes on the rampage in her garden, ripping off the heads of her camellias. As a punishment, Jem is ordered by Atticus to go and read to the old lady.
Shortly afterwards, Mrs. Dubose passes away. Scout is shocked to hear Atticus describe her as the bravest person he ever knew. This puzzles Scout. Not only does she think that Atticus is the bravest person around but she cannot understand how someone as ornery and downright unpleasant as Mrs. Dubose could ever be thought of as being brave. Atticus tells her that Mrs. Dubose had been a morphine addict for a number of years but was determined to beat her addiction before she died. She failed, of course, but her heroic struggle against the evils of drug dependency displayed exemplary courage and earned her the undying admiration of Atticus. Scout learns not just about putting yourself in other folks' shoes but about the many different ways it's possible to show courage.