A couple of hours. And most of them he wasn't awake. But how do you express that? He forces his hands to stay still and not start tugging at his shirt. That's bad manners, he's been told. "Day." It's not exactly that, but surely it would come close enough for the purpose? Will his father be angry that he gave a wrong timeframe? But it's not entirely wrong, and he probably won't hear about this... "Come in night."