Perhaps that was what Draco referred to the night before. He might be under the impression that the wizard who saved his life, and hers too, for that matter, could still be saved. Few would have enough influence to get near the prisoners. Even fewer would have enough influence to aid successfully in the escape of a prisoner as high priority as Aberforth Dumbledore. If Draco's loyalty was to Aberforth, did that mean he only continued to track her and then offer his home to her as a way to get her to help?