Aira's sleepover at Damien's had enlightened Cassidy of their present relationship.
She and Adrian had been with Edward at another part of the mansion that evening. While she was dismayed that she couldn't spend time with Hugo and Joshua again since they're at Olivia's residence at that moment, she still had a good time discussing their big brother and her little sister's dynamic as a couple.
"Still, I'm worried they're progressing too quickly. You know teens these days. They're too eager to try… different things," was what Edward mentioned at one point during their conversation.
"Oh, I wouldn't be too worried about it. I'm sure that those kids know what they're doing. They're smart. Besides, it's a good thing that we're letting them take as many opportunities as they can to be with each other," was what Adrian replied to him at that time, and Cassidy could not help but feel proud of him.