Spocklar actually didn't recognize that the Stranger was in control until it was gone, though it made sense because it had taken over before when she fought Nero. But he did recognize that Sharley was fully there. And he was also somewhat surprised to see her scars fade.
He winced when she coughed up the rest of the blood, and he was glad for the distraction of Marty when she came over. She had to be feeling as weird as he did. He reached down to put a hand on her shoulder. The fact that the zombies were cold didn't bother him anymore--it didn't really matter, they were still alive. But Sharley wasn't one of them now, she would still be warm.
He just watched the exchanges, not wanting to say anything until he was addressed. It wasn't his place at all--he didn't have anything to do with death, he was so firmly planted in the realm of living that he couldn't even be taken out of that.
When Sharley looked at him, he chewed on the inside of his lip before he answered. "I carried you," he said quietly. "You're kind of heavy.."
Spocklar looked down at Marty for a moment, and then he looked at Tanya, before he focused back on Sharley. "Nero did it," he said.