Hermione had taken his hand and was gripping it tightly. He could not look at her, but returned the pressure, now taking deep, sharp gulps of the night air, trying to steady himself, trying to regain control. He should have brought something to give them, and he had not thought of it, and every plant in the graveyard was leafless and frozen. But Hermione raised her wand, moved it in a circle through the air, and a wreath of Christmas roses blossomed before them.
He should have brought something to give them.... what is them, exactly? The deep, sharp gulps? A good quote won't have a pronoun referencing something that isn't established.