No, this story doesn't have a happy ending.  It is a sad story of teenage boys whose mission is to destroy an innocent man's home for no reason other than it is still standing in the town that has been destroyed by World War II bombing.  The boys carefully plan how to destroy the house and do so over a couple of days, methodically and meticulously.  At the end of the story, a truck driver starts his truck and hears a crash behind him as he pulls off.  He doesn't realize that his truck has been tied to a main beam in the home and that he brought the entire home crashing to the ground until he steps out of his truck to look at it.  Mr. Thomas (the homeowner) is devastated when he sees it, but the truck driver laughs at the situation, which adds to the sadness and sheer meanness of what the boys did.