Look mate, there is a saying in my place that 'he who is not ready to save himself, nobody can save that person, no matter how hard they try', being a friend to an addict gambler does not mean you should turn yourself to a babysitter, most especially in a case where the addict him or her self isn't even a baby.
Don't get me wrong though, its not a bad thing to try to help, after all the biblical law commands us to be our brother's keeper, but then, you can only help someone who is willing and in need of help, else your effort will just be wasted one, and if not careful, you might even end up becoming an enemy to the said or supposed friend, this opinion of mine is based on personal experience though.
I think what a gambling addict needs is genuine attention so that he knows that there are still people who try to be kind and care about him. Gradually, this will open his heart to accept the person, and with this gentle approach, the gambling addict can start to open up. After all, there's nothing wrong with trying to pay attention to a gambling addict, especially if we know them well and we think they really need our help.
We all have a different approach in terms of showing our care to a certain individual who already suffering from heavy gambling addiction, some can continue to still being patient while others are just voice it out and do nothing, I guess in terms of help if the person is really dear to us we needed to extend our understanding in hope that with such genuine efforts we will be able to let them realize that they needed to stop and quit with what they already addicted with.
Things that really needed to address in order to stop that problem which already exists inside their mindset, an unbalance way of
gambling always ending up with lots of consequences.