He doesn't sleep, listens to Huaisang and tries to soothe him through the crying, even if he doesn't try to wake him, but it's the final part that has him focused.

Because he knows that tone, that anger intimately, because he's been there, had exacted his own revenge even if not with his own hands. Still he doesn't speak, just lets Huaisang keep sleeping until morning.

But it's enough to have him thinking, considering his options on how to address this when they're somewhere not a discussion conference.