If I were the casino manager I would want to fire the casino worker for interfering with my business but I am afraid there would probably be laws which prevent me from doing exactly that because I am not sure if it would be considered as wrongdoing by the court. In fact the court may see it in a positive light, like he was trying to prevent a gambling addict and a new father from a gambling addiction or something.
From a humane perspective the worker is probably right to tell him off. From a business perspective... Not so good.
As far as I know, in almost all countries casinos are in a "special position" in relation to customers and employees. For example, a casino may not let a person in without explanation, it was originally invented against scammers and still works. I heard something similar about the croupier - if the casino, for some reason or without it, does not want a particular croupier to work, then it fires him without any problems. These are the features of the business.