unfortunately a company could very well much argue that as long as he is not their employee it is none of their business how he is doing mentally which is why it would just be easier to let go an employee having a hard time dealing with things such as addiction
it also doesn’t help that there is a stigma against gamblers, addict or not, they can always claim that he isn’t an addict and he just really likes gambling which is his conscious choice to keep doing
Moreover, I am almost sure that no player will admit that he has an addiction, I mean that he will not admit it even to himself. I do not want to judge him now, it is his choice in any case, and I suspect that he did not play for the money, because in the bank, employees often receive a very good salary, which should be enough for all expenses and desires. And I understand his fear of losing this job, because in Japan, a career can be built in one place for many years, this is due to their culture.