His reaction is honest and real, and shows that he has emotions and feelings as well as logical reactions to his life. He also decides he cannot live with his father when he discovers his father is the one who killed Wellington. These are all emotional reactions to problems, and so he is very capable of love and other strong emotions. His reactions might not be what another person's reactions are, but they are certainly real and important.
In addition, Christopher becomes aware of a terrible hurt inside him because of his father's confession. Haddon writes, "But this hurt was inside my head. And it made me sad to think that I could never become an astronaut" (Haddon 132). That kind of hurt comes from love, and Christopher now knows the pain of loving someone and losing them. This feeling forces him to do things he would never do before, such as leave home, find the train station, and travel to London on his own. It also forces him to think about who he trusts and does not trust. He learns he cannot trust everyone, even those that are closest to him. That is a difficult lesson to learn, but it helps Christopher grow up and mature.
Ultimately, Christopher learns about love in this story, and he learns more about himself. He has to learn how to trust people - especially people that he is supposed to be able to trust, such as his father. Trust is a vital element of love, because you have to trust someone before you can love them. Most of all, Christopher learns to love himself in the story, another proof he is completely capable of love. Christopher lives in a world that revolves around him, and it is difficult for him to let others inside. He is very self-centered because of his disease, but even being self-centered, he still does not really know what he is capable of doing. In the end, he realizes he has limitations, but that he is incredibly talented, as well. He gets an a on his maths, but he also realizes that he can strike out on his own and make his own decisions, even if they are not always the right decisions. He learns to love himself, along with his mother and father, and that is the beginning of his journey into manhood.
While Christopher often compares his mind to the mind of a computer, he realizes that most people do not think the way he does. He believes the difference between humans and computers is feelings. He thinks, "But feelings are just having a picture on the screen in your head of what is going to happen tomorrow or next year, or what might have happened instead of what did happen, and if it is a happy picture they smile and if it is a sad picture they cry" (Haddon 119). However, he has these feelings and reacts to them, just as any other human would. The reader can feel his pain and betrayal when he discovers his father lied about his mother's death, and when he travels alone to London. He might not have all the same reactions that another person might have, but he certainly has feelings, emotions, and needs, and is capable of love, trust, and distrust.
In conclusion, Christopher is capable of the same kind of love that any other person might feel. He is a very wise boy trapped in a body with a mind that can only understand certain logical problems. However, his reactions to his family and his own troubles indicate that he is capable of love and emotion, and he shows his love in many ways, from touching fingers like his family taught him, to his emotional and physical reactions to the news his mother is alive and has chosen to live away from the family. Christopher is capable of love, and love helps him put his life back together again.