What does Jem have to do for Mrs. Dubose in To Kill a Mockingbird?

In chapter 11, Jem, having gotten fed up with Mrs. Dubose's taunts to him about his father, visciously attacked her prized camellia bushes with Scout's wooden baton and destroyed most of the camellias.  He had to pass by her house quite often and she was a cantankerous woman who was dying.  She disapproved of Atticus's defense of Tom Robinson and said spiteful remarks whenever Jem passed by.  When Jem tore up the camellia's, he did it out of anger at her words.  As a punishment, Atticus made Jem go to Mrs. Dubose's house and apologize.  Mrs. Dubose told him that as payment for the ruined flowers, Jem should read to her every afternoon.  Atticus told him he had to do it for one month but it turned into about a week more than a month.  The real reason that Mrs. Dubose wanted Jem to read to her is that she wanted to die free and clear of the morphine she'd been taking to ease her pain.  The reading distracted her and she did die without the addiction to morphine that she'd had.  Because Jem read to her she was able to die without anything having a hold on her, which was her goal.