For two reasons I don't think Nick's gonna be fooled this time.
1. P and P are good with their writings IMO. (Even though they suck at being on time when it comes to delivering the game). Fooling Nick is not gonna be a smart option. It's lame and weird.
2. P and P let you choose between turning on the lights or not. So we can speculate they deliberately wanted us to choose between Nick finding out or not.
What happens? I guess they kick Nick out. Why?
1. It's Fred's house. 2. Nick's a pussy so he won't do shit to his father ( as we've seen many times throughout the game like Jamal fucking Lily in front of him or his friend groping Lily...) 3. Lily is starting to love Fred more and more. As we've seen her being more submissive towards Fred this time. And Lily found out Nick wanted to cheat on her.
So Nick's gonna get kicked out and go to his small shack get depressed or something. And my speculation is Fred is gonna be the prime sugar daddy for Lily and this is gonna be one of the endings of the game.
This is small theory of mine