Voldemort didn't use Avada Kedavra on Snape because he didn't want to kill one of his most trusted Death Eaters. At the very least, Snape survives long enough to have one last meaningful interaction with Harry, ensuring he understands his loyalty to Lily and Dumbledore.
This event took place in the Shrieking Shack during the Battle of Hogwarts on 2 May 1998. During this event, Lord Voldemort murdered Severus Snape with Nagini, as he incorrectly believed Snape was the master of the Elder Wand.
You will be sent to Azkaban if you use Avada Kedavra on students - Hogwarts Legacy
Why was Snape's Avada Kedavra blue?
The intent of the caster is a vital component of the spell. While Snape was still able to produce Avada Kedavra without any intent to kill, being a great wizard, the mix of hesitation and necessity probably resulted in the spell being blue.
At this point, McGonagall begins to gain the upper hand as it becomes clear he cannot further transfigure or counter her attack, so the only way he avoids it is by taking refuge behind a suit of armour that he forces in front of him.
While conferring with Snape about the inevitable outcome of this curse, Dumbledore also asks that Snape kill him when the time is right. Not only would this protect Draco from irreparable harm, but it would ultimately prove Snape's loyalty to the Dark Lord during a critical time.
Voldemort never saw any of his followers as equals; the only people he ever respected enough to kill personally were always his enemies. Think of how few people came out of his wand in The Goblet of Fire at the end! He didn't respect Snape enough to kill him personally.
Ultimately, it's a good thing that Dumbledore's plans didn't work out because if Draco hadn't disarmed the headmaster, Harry wouldn't have gained the Elder Wand's power when he later disarmed Draco. This was proof that, unlike Dumbledore, Harry was destined to reunite the Hallows and become Master of Death all along.
J. K. Rowling stated that wands with Thestral tail hair cores can only be mastered by those who can accept death. Therefore, it would seem impossible for someone like Voldemort, who was obsessed with immortality and therefore unwilling to accept death, to ever master the Elder Wand.
Hedwig's killer is not explicitly identified, so he/she may have appeared in other books, films or video games, but the only known appearance is Harry Potter and the Deathly Hallows and Harry Potter and the Deathly Hallows: Part 1. A popular fan theory based on book canon suggests that Snape may have killed Hedwig.
Simple answer is, that's only in the movies. They often play fast and loose with things that might look or sound cool in the moment but make no sense in the overarching story. Ron never casts Avada Kedavra at Nagini in the books.
So, during the summer between his fifth and sixth years at Hogwarts, Draco Malfoy was tasked with the assassination of Albus Dumbledore to restore his family to Voldemort's good graces. Also at this time, Draco was branded with the Dark Mark. This killed two birds with one stone for Voldemort.
Notably, Voldemort appeared to be entirely unaware of this split, as he later created a seventh Horcrux in his quest to have six, and continued to target Harry Potter despite him now holding part of Voldemort's own soul.
Family. Snape's family background is mostly shown in flashbacks during the course of the last three novels. Snape was born to Eileen Prince, a witch, and Tobias Snape, a Muggle, making him a half-blood (hence the name, "Half-Blood Prince").
To defend her students, McGonagall casts a series of spells Snape's way, but he manages to evade all of them before flying away. But what McGonagall doesn't know is that Snape is actually a double agent working for Dumbledore, so he has no intention of harming her.
He promised to protect Draco Malfoy from harm and guide him whilst he attempted to perform the task the Dark Lord had asked him to do: to kill Albus Dumbledore. Snape was actually a double agent working for Dumbledore, who requested Snape to kill him anyway to spare him of a painful and humiliating death.
Thus, the answer is simple - Snape mistreated Neville as he was nearly the chosen one. Had Voldemort picked Neville instead of Harry, Lily's life would have been spared. Snape relieved his dark past through Neville Longbottom and therefore resorted to mistreating and insulting the almost-chosen one of Harry Potter.
What was Minerva McGonagall's reaction to the death of Severus Snape? Initially, it was likely one of breviloquent satisfaction; it would almost immediately evolve into a deepest sorrow and devastation. …
Malfoy spots Harry and casts a Cruciatus curse; Harry, defending himself, using the Half-Blood Prince's Sectumsempra spell without knowing its effects. To his horror, it gashes Draco's face and chest, spilling his blood everywhere. Moaning Myrtle flies off, screaming.
Why didn't Harry get in trouble for using sectumsempra?
When Harry critically injured Draco Malfoy with the Sectumsempra curse, it was actually enough to have him expelled, as Professor Minerva McGonagall stated Harry was lucky not to have been, due to Snape giving lenience to prevent others from finding out that he was the one who invented the curse.
