I could see it easily fitting in. You've got two brothers plotting against you and your daughter, it's not that far of a stretch to see them planing an abduction and forcing her to do things. Or the daughters friends may be a bit kinkier and wild then they let on. There are a lot of places where it can be slipped in. And that's just characters that are already there, he could always slip in a mousy mail room worker/intern at your job that's a little too fond of her pets. honestly its just like the real world, it may not fit your (or my) obvious narrative, but you never know who's getting their freak on behind closed doors. But when you see it, you end up going, "ooooohhhhh, that explains a few things" lol (of course then there is the flip side example of the serial killer who "was such a nice man" but yeah that would be you being correct and it doesn't fit in the story but was thrown in for gits and shiggles.)