In "To Kill a Mockingbird," what does Mrs.Dubose want from Jem as payment for ruining her camellia bushes?

Jem must read to Mrs. DuBose as punishment for ruining her bushes, even after she was the one to say terrible things about Jem's father, Atticus.  Each night when Jem reads, Mrs, Dubose sets a timer to mark the length of time he reads to her.  Each night, she lengthens the amount of time Jem is reading.  What Jem does not realize, but Atticus later explains to him, is that Mrs. Dubose is addicted to morphine.  Her illness and her pain made her the curmudgeon that she was.  Jem's reading to her distracted her from the pain so that she would not take the morphine during that time.  As she lengthened the time, she took less and less of the medicine until she was no longer addicted.  It was her wish to die without the addiction, and that is what Atticus described to Jem and Scout as "real courage".