This was once a failed experiment to me, we've done it before for a family friend that got addicted to gambling and things look better and I personally spend a week with this fella just to make sure he won't be alone, I thought him few other things that can keep him busy and make money in the process, but after several months he went back into gambling, my point is when are you not going to leave them?
There will be a time where they will be alone, the best way to beat gambling adddict is if the gambler is willing to beat the addict himself, they need to put in the work themselves, and that's when the chains of addiction will break finally.
If you are the only one that has the mind to save a gambling addict from addiction, you have alreday failed before you begin.
Sorry about that, but this is why despite the best intentions of their family members and their friends, the decision and the conviction to leave their gambling addiction behind must come from within the addicted, if this is not the case then it does not matter how much you try to help them, at some point you will have to do something else other than helping them, and once they find themselves on their own they will go back to their old habits and everything that was done for them would be for nothing.