The relations between Weasley and Malfoy families were not started hundred or five hundred years as like the other wizarding pureblood families. During Hermione's third year, Lucius had gone into azhkaban - all his properties getting ceased, he didn't leave any in the name of Narcissa or Draco, so that they stood with nothing but Arthur Weasley took them into the burrow, when no one took them in.