how would you describe christophers family, once he moves back to swindon? what has changed for the better?

When they get to the house in Swidon, Christopher's parents argue, and his father goes to stay with a friend. The school arranges for the invigilator to come in so Christopher can sit his A-level, even though he is very tired. Soon Christopher's mother gets a job, and the two of them move into a room in a big house.

Christopher still won't talk to his father even though he has to stay in his house from 3.49 until his mother picks him up after work at 5.30. Christopher's father proposes that they do a project together, so he can show Christopher that he can be trusted. He reveals a golden retriever puppy - the puppy will be Christopher's if he goes to his father's house to walk it. Christopher begins spending more time at his father's and starts planning things for the future: to do further math A-level next year, then physics A-level the year after, then get a first class honors degree and then be a scientist. He knows he can do this because he solved the mystery, because he went to London on his own and because he wrote a book.

The novel ends on a note of total happiness and hope. Not only has Christopher found his mother and normalized relations with his father, but he has also begun to learn to express his emotions in a way that is understandable by most people. He has written this book, which he knows is a huge accomplishment. But he also notes that his A level made him feel glad by drawing a smiley face - perhaps he doesn't smile himself, but he can identify his feeling with a facial expression. He has made progress.