I think that you should be able to answer this question quite easily, if you keep the following background information in mind.  Mrs. Dubose, during the entire time that Jem was reading to her, was fighting off a horrible addiction to morphine.  So, she was in the midst of that intense struggle, attempting to come clean before she died.  She was in pain, suffering from withdrawals, and fighting the battle of her life.  After Jem and Scout leave that last time, she knows that she has won the battle against morphine, but that she is not facing imminent death.  So, as you answer this question, keep in mind that whatever thoughts that she has will reflect her joy over getting over an addiction, her relief at not having to deal with withdrawals anymore, and her sadness at her upcoming death.  She'll be proud of herself for kicking morphine, at peace with the fact that she can die clean, but a bit sad and anxious about coming death.  So, just keep in mind that mindset, and answering this question will be a piece of cake!  Good luck!