Nael van Darnus is dead and gone. What we're seeing is a memory projection, not an actual aetheric being such as a Primal. There's a reason Louisoix and Van Darnus didn't say a word, they aren't Auron who could interact with things despite being dead. SE's way of telling the Battle of Cartaneau will be through these events. If Louisoix were indeed alive, he would have atleast said something. He was never a silent hero, he was the leader of the Circle of Knowing and the Archons. Also we would have access to the Echo, potentially, and be able to witness the Battle of Cartaneau through his own eyes. Instead it's merely a projection, both Louisoix and Van Darnus "know" who we are based on their memories. It's similar to how the characters in XIV had forgotten about us 1.0 players because of the distortion of the aether, probably due to the spell Louisoix used, sending us away and manipulating the aether to save us.