A gambling drug addict, struggles to reunite with his family while escaping an iconic resort’s sinister nightman with pious motives.

"On an island resort, a gambling drug addict searches for his family while pursued by a sinister nightman who punishes sinners."

- Interesting to contemplate if the protag is a gambling drug addict or a drug-addict gambler. Kind of a chicken-and-egg situation. Did the gambling lead to drugs or the drugs to gambling? [Ah, I see you answered this in a comment, favila.]

- Wasn't sure what kind of resort you intended. Anything with enough isolation will do.

In the end, the night man is probably the lead character, (A hallucination) the lead just doesn't know it because he is a prisoner of his own devise.

I get the reference to the lyrics of the "Hotel California" by the Eagles:

"Relax, " said the night man,
"We are programmed to receive.
You can check-out any time you like,
But you can never leave! "

But I am unable to get a handle on the fabulist world of your concept. And I find the psychology that you give to explain his addictive behavior puzzling.