In his pov he would be in love with his step sister so… his opinion is irrelevant
I do not like the step-sibling relationship thing AT ALL.. but I understand I am part of a small group BUT why does it invalidate his feelings??? He wanted to show the world his long-lost BLOOD sister is alive again. I do not think his intentions were dubious.
We all feel angry because we are watching this through Penelope's POV and are forced to feel what she feels no matter the situation.
The reason he brought her wasn’t because of that tho.
He just wanted to show that Penelope isn’t his sister so he can have those feelings for her that’s how it was explained in the spoilers
Because dad and the other brother both understand that today is Penelope’s day. Regardless of their own personal feelings about getting a daughter and sister back, they understand that a woman’s birthday and coming of age ceremony can only ever be done once. This is it. Usually derek would act in a way befitting the heir to the family but today, he’s acting like a spoiled brat who was clearly told no and he did it anyway. He arrives late with the absolute worst person for the whole families reputation. Not just Penelope’s. Penelope is their sister and daughter for literally all intents and purposes because she’s been living with them since she was a child and has been integrated into the household. She has their last name. She’s as much family as this pink haired bimbo is. In fact I’d argue she’s MORE family.
He just wanted to see Penelope reaction
....but imagine if we have Derek's POV... that other lady is his REAL SISTER which he thought his carelessness caused her to be missing or dead. Of course, he won't want to hide her.