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.