He didn't think she would know. They didn't know, so why would she? "Yeah, I am." If he wasn't willing to risk it then he would have told her to go away already. But he hasn't. He told her to stay.
He watched her finally walk further into the living room. "I will tomorrow." He wasn't going to tell Newt anything tonight. Newt needed to rest and not get agitated. He could do that tomorrow when he felt better.
"Are you going to sit down or are you going to stand there all night?"