Friday the 13th
The amnesiac protagonist sets himself up to finally murder the guy who’s been manipulating him.
Memento
His mom is dead!
Psycho
The ones who think they are being haunted are actually the ghosts.
The Others
He Zuckerbergs his best friend! (lol)
Assuming you meant, “He thinks Zuckerberg’s his best friend!”:
The Social Network
Next:
Two of the three get shot by a firing squad at the end.
It’s been four weeks. 
Could we please have a clue? 
Breaker Morant?