'Mellon'. Probably an offhanded figure of speech for her, but for someone like him, who knows parts of her language... it's life-changing. For all his effort, for all his attempts to look like an asshole, to push people away... he was being called a friend.

He doesn't pass out while she's gone, too in shock to do so. He just stares up at the ceiling, hands shaking for entirely different reason besides illness now.