Thank you for pointing this out, this is what's been missing in all the people that's replying to this thread: empathy. Just because you think it's going to work doesn't mean that it's going to be effective in practice and it's going to be so unempathetic of us to tell what works and what not, addiction is complex and how to solve them is literally different for each individual even if there's some similarities to the possible solution, each person will recover differently.
While the repercussions each addicted gambler could suffer are similar, the reasons that could push a person in this direction are unique to each person, it is because of this that curing an addiction is so difficult, as you cannot use the exact same therapy you used on a patient and hope that it works with another one.
Still given enough time and the right therapy those people should improve quite quickly, but this requires they actually realize what is going on and decide to accept that help.