Why did Dumbledore not tell Harry how to destroy the Horcruxes? The reason that Dumbledore keeps his knowledge about the Horcruxes secret, (and presumably this is the same reason he did not tell the Order), is because he did not want the word to get around that he knew so many of the Dark Lord's secrets.
Dumbledore knew that destroying Voldemort's horcruxes was the only way to truly defeat him. He believed that Harry was the one person who was smart, courageous, and perhaps lucky enough to find and eliminate all the horcruxes.
Dumbledore was afraid that Harry may repeat his youthful sins of searching the deathly hallows for wizard dominance. he was afraid the untimely information would damage Harry's motive to destroy voldemort.
Question number one: Why didn't Dumbledore just give the sword of Gryffindor to Harry instead of leaving it to him in his will? He knew even before his death that Harry would need the sword to destroy Horcruxes, and he must have known that the Ministry would not let Harry get the sword.
He didn't tell Harry about the Prophecy, because he thought it would affect Harry's peace of mind and happiness , when he comes to know that he's the chosen one and that his parents died due to a prophecy.
However, Voldemort chose Harry as his target, who was, like himself, a half-blood, rather than the pure-blooded boy named Neville. Voldemort chose Harry as he believed Harry was the most danger to him and he saw himself in Harry before even seeing him.
The only reason why it was Harry is that Voldemort thought he was the child the prophecy was talking about. By targeting him and trying to kill him, Voldemort marked him as his equal, while Neville got to live his life without that burden (though that doesn't mean he had an easy life).
“Dumbledore didn't want to lose his wand at that point and Draco disarmed him. So that meant that the wand gave Draco its allegiance, even though Draco never knew it, even though Draco never touched it. “From that moment on, that wand gave its allegiance to Draco, and it wouldn't work as well for anyone but Draco.”
Phineas Nigellus's portrait inside it overheard Hermione and reported that to Snape. Snape thus knows that Harry and Hermione are in the Forest of Dean, though not exactly where; the Forest of Dean is a largish place, several wooded sections totaling about 40 square miles.
The three Deathly Hallows – the Invisibility Cloak, the Resurrection Stone and the Elder Wand – have tempted many a wizard over the years.
He would always resent Harry for being James' son instead of his. Snape even said that he didn't want anyone to find out that he was protecting Lily's child, “especially Potter's son” (pg. 679 of Harry Potter and the Deathly Hallows) because of his hatred for James.
He finds out for sure immediately after Nagini's attack on Arthur Weasley. This night is significant in many ways. While Harry sleeps, he enters Nagini's mind.
He has grown afraid of Harry's connection to Voldemort. Perhaps Voldemort, knowing Dumbledore's love for Harry, would possess Harry and provoke Dumbledore to kill him. So, Dumbledore attempted to avoid Harry throughout Book 5 for Harry's own good.
So why wasn't the Horcrux residing in Harry's head destroyed when he was bitten by the Basilisk? The answer is simple: He didn't actually die. Fawkes quickly healed the bite wound with his phoenix tears just in time. Case closed.
Voldemort wasn't aware of Harry being a pseudo-horcrux because he didn't plan it, and Harry didn't know either until Voldemort “killed” him, but he actually killed the piece of soul kept in him.
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.
Draco's refusal to reveal Harry's identity to Bellatrix was not because he liked him. It was because he believed that Harry was the only chance they had at defeating Voldemort. At first, Draco admired and revered Voldemort until he threatened his family's safety.
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.
Severus Snape and the Deathly Hallows
He even sent his Patronus to guide Harry Potter to the sword of Gryffindor (a known Horcrux-killer) in a nearby lake.
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.
For all intents and purposes, this act only solidified Harry's suspicions that Snape was working against Dumbledore the entire time. But there were parts of the story Harry didn't know, including that Dumbledore was already dying and had asked Snape to kill him when the time was right.
The final book, Deathly Hallows, explains this. Snape HAD BEEN a Death Eater. He later renounced his connections with that group, but no one besides Dumbledore knew for sure whether he had truly switched sides, or was just faking it. Dumbledore, alone, knew the truth.
While most fans agree that Harry is the unrefuted Chosen One, the final Deathly Hallows film (in particular) sways heavily toward highlighting a heroic Neville, revitalizing the debate regarding which boy is better suited for the iconic title.
In the end, both were essential to Voldemort's downfall, fulfilling the possibility that both Harry and Neville were, in fact, the Chosen One. While Harry delivered the final blow to destroy Voldemort, Neville destroyed the final Horcrux which allowed Harry to end Voldemort.
Harry is the Heir of Slytherin (through his mother's side) and also related to Gryffindor (through his father's side) though the current Heir of Gryffindor is Neville.