The only problem with how Ignis uses him to hold himself up is that Noct isn't exactly steady on his feet, either. Barely keeping himself up after this sudden shock. It's why he didn't even hesitate to hold onto him at first sight.

"We should... sit down."

Because this information is a little much to take in. Especially the thought of Ardyn attacking Ignis. Because he'd told him that he'd seen his ship, not-

The cot beside them is empty so he's just... Going to sit down there, now.