So why did he conceal this from Snape and act as if Harry had to genuinely die? Well, firstly because Dumbledore conceals things from Snape as a matter of routine, such as the existence of horcruxes generally. But secondly because he needs Snape to think Harry has to die so that he passes that belief on to Harry.
Dumbledore now knows what he meant by going further than anyone else in overcoming death. Worse still, he now knows or at least strongly suspects that Harry is also a horcrux, and that he will therefore have to die in order to kill Voldemort for good.
Dumbledore lied to Snape. What Dumbledore wanted was for Harry to believe he had to die, in order for Harry's “sacrifice” to give the same power of protection to the defenders of Hogwarts that Harry had gotten from his mother.
Since Harry's birthday is the 31st of July, and the narration stating "few weeks", he must have arrived at least two weeks before that. In Deathly Hallows, during the trip in Snape's memories, we learn that Dumbledore asked Snape to mercy-kill him right after Severus saved him from the curse the Ring of Gaunt carried.
No, he meant Voldemort to think it his. It seems highly unlikely that Dumbledore planned that Snape would have to die. He likely had reasoned that Voldemort would consider stealing the wand from his tomb to be enough to master it, which he did, for quite some time.
Later in the year, McGonagall duelled with Death Eater Alecto Carrow during the Battle in the Astronomy Tower and later learned of Snape's murder of Dumbledore. McGonagall was initially appointed as Headmistress, but was demoted after Voldemort took control of the school and placed Snape as Headmaster.
Draco Malfoy's mother Narcissa was cold, cunning and devoted to the Dark Lord. But she was also a mother, which meant she was willing to risk everything to make sure her son was safe. When Harry survived Voldemort's Killing Curse for the second time, Narcissa pretended he was dead so she could get to Draco.
Snape took the fall instead at Dumbledore's insistence. But, that's not all. Dumbledore was also aware that he wouldn't be alive for long because he had been cursed by the Horcrux ring. Instead of suffering a painful death, he urged Snape to end his misery.
“You disgust me,” said Dumbledore, and Harry had never heard so much contempt in his voice. Snape seemed to shrink a little, “You do not care, then, about the deaths of her husband and child? They can die, as long as you have what you want?” Snape said nothing, but merely looked up at Dumbledore.
He played the part of a loyal servant to Voldemort so well that Voldemort thought of Snape as his most loyal and capable servant. He regretted the (supposed) necessity of losing his (supposed) most valuable servant. He felt nothing for Snape as a person — the only person who mattered to him was himself.
Voldemort intentionally made six Horcruxes, but when he used Avada Kedavra on Harry, he unintentionally created a seventh Horcrux. Instead of dying, Lily's love for Harry created a counter 'curse' known as Sacrificial Protection and saved Harry.
Because Voldemort literally took over the Ministry of Magic. And immediately after Dumbledore's death, Snape disappeared with the rest of the Death Eaters from the Astronomy Tower. The Ministry had a hard time tracking any of the key players in Voldemort's ring.
Similarly to Harry, Snape's patronus represents a person. In the memories he gives Harry before his death, Snape shows Dumbledore his patronus, using the form to prove his love of Lily Potter, Harry's mother.
Who would have guessed that Snape could love anyone, let alone Harry Potter's mother. He didn't protect Harry because it was the right thing to do; he didn't risk his life by being a spy for Dumbledore because he enjoyed living on the edge; he couldn't even stand Harry, yet Snape died protecting Harry's life.
And so it is nearly certain that from the night James and Lily were killed, Dumbledore planned for Harry to die ' and not only to die, but ideally to sacrifice his life willingly as Lily had done in order to afford the Light side the greatest chance of destroying the self-proclaimed Dark Lord.
In order to conjure the avada kedavra curse, you have to want to kill your victim. We all know that Voldemort could easily kill a child without an ounce of remorse... but not Snape. Snape didn't want to kill Dumbledore, and this was why the spell was blue instead of the usual green.
Three reasons, really: firstly, as part of Harry's transition from boyhood to full blown adult wizardry, the death of Dumbledore represents the point at which Harry is fully exposed to the fight against Voldemort - his insistence on not briefing Prof McGonagall (as the new head of Hogwarts) on Dumbledore's final ...
Professor Snape is dead on Voldemort's orders, and Harry saw it all. In his dying moments, he told Harry to take his memories and look at him one last time. Voldemort's voice then sounded through the corridors, challenging Harry to meet him in the Forbidden Forest in an hour. This is the end.
Narcissa's greatest moment, however, was when she chose to betray Voldemort in Harry Potter and the Deathly Hallows. Not knowing whether Draco was alive or dead, Narcissa chose to lie to the Dark Lord rather than risk losing her son.
This nuance was lost on Lord Voldemort, who wrongly assumed Severus Snape held the Elder Wand because he was Dumbledore's killer, when in reality Draco had disarmed Dumbledore before Snape arrived on the scene, making Malfoy the wand's true new owner.
Ultimately, his need to survive and protect his family would lead Lucius to betray Voldemort. With the Dark Lord defeated, he and his wife Narcissa turned in every Death Eater they could to avoid being imprisoned in Azkaban.
Knowing that Snape has been on the Dumbledore's side for all seven of the Harry Potter books reveals him as an extremely brave man and a truly skilled spy. Snape has had to face and deceive the terrifying Lord Voldemort constantly.
After it was revealed that Dumbledore was devastated by the accidental death of his sister during a fight with Grindelwald and his brother, Aberforth, it became clear that Dumbledore's deepest desire, and regret, involved his family.
Dumbledore reveals how thoroughly he loves Harry. Harry is brave, and Dumbledore is proud as any father would be. More than that, Dumbledore succumbs to a parent's weakness; he cares more about Harry's happiness and wellbeing than the wizarding world he is trying to protect.