a simple solution to an impossible problem

This is the day after Oskar and the renter dug up his grandfather's coffin, and Oskar discovered that Mr. Black is gone. He also discovers that Abby Black left him a message (that got interrupted and lost) eight months ago. The reason why Oskar never answered his machine is because he was too stubborn and nervous to answer it. So when Oskar heard the message he visited Abby, and he found out that Abby's ex-husband knew about the key. YES! it took long enough. His name is William Black, and hehas been looking for the blue vase with the key in it for over two years. William had sold the vase to Oskar’s Dad two years before. Oskar’s Dad had said it was an anniversary present for his wife and that they were going out for dinner. The night after William had sold the vase, he discovered there was a key in it that opened a box at the bank.

Oskar desides to visit his grandmother, but she wasnt home. The renter was there and oskar tells him all about the story of the key. Oskar also told him about all the people he met and what he learned from them. He also let the renter hear the messages his dad left on the message machine. I still dont understand why the boy would tell the renter about the key and why would he let him listen to the messages his dad left him. That really confueses me, i just dont understand why he tells him. If that were me i wouldnt telll him all about the key. When grandpa writes one final letter to his son even though he died 2 years ago, he writes about how when he read the newspaper about his son dying that he decided to go back to New York to mourn and live again. He then gets in touch with Grandma and she allows him to stay in the guest room. He also admits to following oskar around while he was going to visit all the blacks. I think that it is interesting how the grandma still lets him stay in the guest room after him leaving her when he found out she was pregnant. Also i think it is interesting that grandpa admits to following oskar around.