When they get to Slughorn's house, things look rather scary. All signs point to a violent attack, and they walk around the rather devastated living room. Dumbledore knowing Slughorn better quickly unmasks Slughorn, who had created the whole scene and was in fact hiding in the living room as an armchair.
Slughorn is revealed to be a nice, fussy old man who likes to be associated with famous and powerful people.
"Slughorn gazed into space for a moment or two: He seemed to be thinking over
Harry's words."Well, yes, it is true that He-Who-Must-Not-Be-Named has never sought a fight
with Dumbledore," he muttered grudgingly. "And I suppose one could argue that as I have not joined the Death Kilters, He-Who-Must-Not-Be-Named can hardly count me a friend . . . in which case, I might well be safer a little closer to Albus. . . . I cannot pretend that Amelia Bones's death did not shake me. . . .If she, with all her Ministry contacts and protection . . ." ""Well done, Harry," said Dumbledore. "I didn't do anything," said Harry in surprise. "Oh yes you did. You showed Horace exactly how much he stands to gain by returning to Hogwarts. Did you like him?" "Er..." Harry wasn't sure whether he liked Slughorn or not"
When Dumbledore and Harry Apparate to the Burrow Dumbledore informs Harry that they'll be taking private lessons together. He praises Harry on how well he seems to be dealing with Sirius's death. He lets Harry know that he should tell Ron and Hermione about the prophecy regarding him and Voldemort, because he needs his friends. He also says something about the OWL results will be there the next day.
"This small encounter shows the amount of faith Dumbledore has on harry and the amount of loyalty shown by harry to Dumbledore. Moreover he uses Harry as a tool wherever he wants to accomplish important things"