Catherine is also becoming more and more ruthless in her pursuit of power, which is something that Aélis does not approve of. Aélis is a kind and compassionate person, and she does not like seeing the violence and cruelty that Catherine is capable of. This difference in their values is another thing that has driven them apart.
Despite all of this, Catherine and Aélis still care about each other. They have been friends for a long time, and they share a lot of history. However, their relationship is not what it used to be, and it is unlikely that it will ever be the same again.