I feel like Daddy Warbucks already knew they were siblings, possibly even at the time he met Namwoo. They keep mentioning enjoying cold beverages the siblings have in common. Daddy Warbucks used to get Namwoo hot coffee until his sister mentioned they prefer cold. After that chapter he started getting Namwoo cold beverages.
Just my observation tho, I could ve overthinking
💜Shes addicted to reading Yaoi💜
