How does Jem develop empathy and tolerance by reading to Mrs. Dubose in Harper Lee's To Kill a Mockingbird?

In Chapter 11 of Harper Lee's To Kill a Mockingbird, it was not so much the actual moments Jem had of reading to Mrs. Dubose that taught him lessons of empathy and tolerance but rather the revelations he had afterwards.

While reading to Mrs. Dubose, Jem was too young to understand what he was witnessing and unable to see Mrs. Dubose as anything but a nasty, sick old woman who had revolting fits. As her fits lessened, her insults increased, and Scout notes that "through the weeks [Jem] had cultivated an expression of polite and detached interest, which he would present to her in answer to her most blood-curdling inventions" (Ch. 11). Hence, it can be said that the more he hears her insult his father, the more he is able to stoically tolerate the insults, knowing the insults are meaningless. Yet, when Mrs. Dubose finally puts an end to their reading sessions, Jem is nothing more than jubilant, showing us that he actually had not come to increase in his understanding or tolerance of her the more time he spent with her. It's not until Atticus explains her situation that Jem comes to realize the true value of Mrs. Dubose and truly learns about empathy and tolerance.

Soon after the experience, Mrs. Dubose dies. The night of her death, Atticus explains to Jem that Mrs. Dubose had been a morphine addict due to pain medications she had been prescribed by her doctor for her illness for years. Yet, being a strong woman, Mrs. Dubose had decided she wanted to "leave this world beholden to nothing and nobody" and had determined to rid herself of her morphine addiction (Ch. 11). She had used Jem's reading as a means of distracting herself from her withdrawal symptoms. It is because she was strong enough to break herself of an addiction, despite the amount of pain she was in, that makes Atticus see her as the "bravest person [he] ever knew" (Ch. 11).

It is after Atticus explains Mrs. Dubose's situation and his own perspective of her that Jem is able to see Mrs. Dubose for her true worth. Jem is able to see her as his father saw her, as a "great lady" (Ch. 11). Jem's new perspective of Mrs. Dubose also allows him to finally truly be tolerant of others' differences because he was finally able to see Mrs. Dubose as having both a good and bad side. In addition, Jem is finally able to feel true empathy because he is able to see that Mrs. Dubose's illness provoked her bitter tongue and is able to see how courageous she was as she faced her pain on her own.