@anapuno_
The amount of people that never read the one shot description.
If both do not even consider the other to be real siblings then who freaking cares.
Ani is just using him to protect her in the future by getting on Dietri's good side and is fully aware that they are not related, Dietri does not even look at her look a family member(family means nothing in this house) but as possible tool in the future.
He was probably the one that saved her too since Ani somehow survived those knights, meaning he knows they are not blood-related.
If you want to say that stuff, then it needs to work, just like Viridescent Crown, there is no sibling bond and no family bonding in this house.
That only works in settings that have a family, like Beware of the Brothers.