"It is not, but it is highly recommended. It is a basic check on temperature, reflexes and to tend to any injuries you sustained before entering Dream Width." Not that Cor looks like he has any visible injuries but...

"If you wish I could accompany you there. I went with his Highness once we arrived." To both keep an eye on the doctors but also make sure Noct is fine. Ignis can do a lot of things but he's not a doctor.

"That is correct," Ignis confirms with a sigh. "I am afraid that we don't know how this happened, only that we were pulled into Dream Width nebula and then picked up by spaceship later." His eyebrows narrow as he thinks about Prompto and Noctis, "Prompto and his Highness... they come from a time long after what happens to me." In Altissia.