When Harry facesVoldemort,
Voldemort pointed his wand at Harry & shouted,"Avada Kedavra"
Voldemort thought Harry is dead
But actually Harry gets escaped & the horocrux of Voldemort inside him dies.
In a total excitation, Voldemort doesn't notice that & marches towards Hogwarts'.But he totally thought he is safe.
There is only one horocrux left.
that is the snake beside him (V).
When Voldemort reaches the Hogwarts'
He(V) laughs with a sense of triumph.
At that moment,Harry gets the sword of Gryffindor & kills the snake by following behind Voldemort & Death Eaters.
After he(H) kills her, Voldemort dies & most of the death eaters are captured by Aurora.
& Everyaurora breaks down the wands of Death Eaters.
So,Harry succeeds to prove the Prophecy true & he at the last moment says good bye to his parents & god-father.
Those who dies by the Death Eaters are revived due to break down of their wands.
Harry at least gets some loved ones back in his life.
Harry becomes happy & Severus Snape becomes Harry's guardian from that moment.
He(S) also becomes the principal of Hogwarts'.
He gets Lupin,Tony back in his life.
George becomes happy after getting Fred,his twin, back.