To start off, let’s lay out what the secret ending entails. After the credits roll, we see illustrations of several key moments in the Dragon Age series. This includes Loghain betraying the Grey Wardens in Dragon Age: Origins,

But The Veilguard ignores all of that in favor of painting the Crows as purple spandex-wearing action heroes with hearts of gold. The only character who ever questions the Crows is, conveniently, an evil power-hungry traitor to the country. So Rook never gets put in a position to challenge or question Lucanis' loyalty to the family's goals.