Christopher’s mother, Judy, died two years before. One day when Christopher came home from school, no one was there. When Ed got home, he asked whether Christopher had seen his mother and then made a number of phone calls. Afterwards, he went out, and when he returned he told Christopher that he wouldn’t see his mother for a while because she was in the hospital and couldn’t be visited. She had a heart problem.
It finally becomes clear why Christopher discusses his mother in the past tense. All of Christopher’s information about his mother’s death comes through his father—something that seems normal at first, but becomes questionable later. Additionally, it later becomes clear that Ed made up a heart problem specifically because his wife was having a love affair.
Christopher wanted to bring his mother food, but Ed said he would buy some and bring it to her when Christopher was at school. Christopher decided to make her a get-well card, and Ed promised to take it to the hospital.
Although Christopher seems to have been very nonchalant about his mother suddenly being hospitalized, he expressed his care for her by wanting to give her food and a card.