[ Regardless of whatever Iroh says in response, Zuko doesn't respond again for many hours more. But Iroh will get a text later that night — maybe around 22:00, which is late for these early-rising firebenders. That's basically bedtime! And indeed, Zuko's coming over for a, uh... impromptu slumber party... ]
text; several hours later, well after nightfall
uncle im coming over