Aries made difficult decisions in the past two years; one of them was agreeing to what Maximus wanted, and the other was keeping Dexter away from her. Her only condition to London Leviticus is to make sure Dexter will be safe. Dexter was still unconscious when she admitted it to the House Leviticus, and she didn't hear anything about him since.
There were times London would mention her brother, but Aries would stop him. Obviously, she was overjoyed when she heard Dexter had regained consciousness, but then again, she didn't have the leisure to rush to him.
In other words, aside from Abel, Isaiah, and many other people who were close to her heart, Dexter also didn't see or talk to her for the past two years. One could imagine his frustration knowing she was just around, but there was no way to approach her.
Thus, explained the surprise on Aries's face, standing face to face with one of the people she missed the most.
Dexter.
