Actually, he almost killed him by throwing Gryffindor's Sword into a lake: Harry almost died when he tried to retrieve it.
Snape
tonks, lupin, voldermort, a part of harry(a hocroux), george, colin creevey, crabbe, snape, bellatrix lestrange
The Patronus that led Harry to the sword was Snape's Patronus.
Voldemort killed Snape.
I believe you mean Snape, as in Severus Snape. Yes, he was good. Harry finds it out after Snape's death in Deathly Hallows.
Yes
Snape dies in Harry Potter and the Deathly Hallows (book 7, the last) on page 658 and his last words, spoken to Harry, were "Look ... at ... me ..."
Harry Potter and the Deathly Hallows Part 2.
Towards the end of the book 'Harry Potter and the Deathly Hallows', Voldemort orders his snake Nagini to kill Snape. As Snape is lying on the floor taking his last breaths, he gives Harry memories that relate to his protection, conversations that Snape had with Dumbledore and memories showing how Snape fell in love with Harry's mother. Harry then viewed these memories in the pensieve and was forced to realise that Snape had been attempting to protect Harry and was acting as a spy for Dumbledore all along.
Severus Snape was headmaster in book seven: Harry Potter and the Deathly Hallows.
Not directly. Snape shows Harry that he was actually always helping him. He protects Harry, but still kind-of hates him.
I seriously doubt it, because Snape's parents aren't in Deathly Hallows, not even in a flashback. Snape's parents appear only once in the series, when Harry breaks into Snape's mind in Order of the Phoenix and sees some of Snape's childhood memories. And that's only in the book, not the movie.