Responses
They wanted the business connection though for their family. But since the FL is not really considered "family" to them but a pest, she is not deemed worthy enough for such a match. Which lol I think is what kinda drove the "dad" into an insane yandere, the one he actually wanted and is better suited for him was made to be his "daughter" and he is married off to her ailing much older sickly mother.

If he is young and the daughter also adult. Why don't they just married them instead of the mom lmao. Well i think author rlly want this to be stepcest thing haha