Childermass doubts that what she wants is chocolate, but he obliges Norrell's offer after a moment, standing straight and moving to fetch a cup for her. He may be the one generally calling the shots here, he might be more present in the situation than Norrell himself, might be more conscious of how to approach it and how to get answers out of her. But he's still only the hired help, and if Norrell wants him to serve drinks then he must serve drinks, as any hired help must do.

He approaches her again, the drink in hand, holding it out to her as he does. "It's just chocolate," he says, as if he is reading her thoughts as to what there might be in the drink. "Though it might be hot. Drink. Calm yourself." He glances back at Norrell, knowing the other man would prefer him approach this like a gentleman rather than digging the answers out of her like he could. After a moment, he leans forward closer to her, waiting for a calmer moment before grumbling out, "There must be something you can tell us. Where does he live? Is it within the territory?" That would make sense, if this has anything to do with the fae themselves.