In Chapter 11 of "To Kill a Mockinbird," how and why does Lee create sympathy for Mrs. Henry Lafayette Dubose?

Atticus' greatest desire for his children is to develop the ability to put themselves in someone else's skin. Lee hits the theme of empathy consistently as the scope of Scout's awareness grows. Lee starts us first by investigating the cruelty of children from several angles, (Walter Cunningham, Miss Caroline's ineptness, etc). The circle widens to further include those who seem to deserve empathy, Dill, Miss Maudie, and those who seem to deserve nothing but scorn and retribution. Mrs. Dubose, Francis and Aunt Alexandra seem to be beyond the scope of empathy. But Atticus is able to guide his children into overcoming the ego-centrism that defines us all in our early development.

Her morphine addiction, withered physical capacity, and marginalized importance carve her into a niche where she is left cornered, frightened and weak. Her only reaction of lashing out violently against a threatening and changing world is understandable, though repulsive.