Ele não foi atingido pela maldição da morte. Ele foi acidentalmente atingido por Sectumsempra, por Snape que estava apontando para outro Comensal da Morte.
Now Harry was flying alongside Snape on a broomstick through a clear dark night: he was accompanied by other hooded Death Eaters, and ahead were Lupin and a Harry who was really George ... a Death Eater moved ahead of Snape and raised his wand, pointing it directly at Lupin’s back –
‘Sectumsempra!’ shouted Snape.
But the spell, intended for the Death Eater’s wand hand, missed and hit George instead –
Deathly Hallows - page 552 - Bloomsbury - The Prince's Tale