More about MakornNathee???
Nathee thinks Makorn has a 2nd son because of a photo of cute little Diao that he keeps close and calls "a very precious person".
After Nathee asks about the picture, because he recognizes Kuea standing beside Diao (Nathee and Kuea run in similar circles), makorn explains Diao is Yi's fiancée, and he loves him as deeply as he loves his son.
So Nathee promises Makorn that, when they're all ready for Nathee to be revealed, he will absolutely love Diao with all of his heart too.
It is implied after the events of Naughty Babe that Makorn does reveal Nathee, and he is fully embraced as part of their family.
Also, Nathee changes his last name, becoming Nathee Chen, just as Diao becomes Tacha Chen.
Makorn Chen, eternal winner of BL Father of the Year