If you know anybody trying to stop the addiction of gambling to become better for themselves and their family, try and show them support by not criticizing them. If you observe that they experience some kind of relapse and go back to gamble even when they said they were not going to gamble, try to encourage them to remember why they wanted to stop gambling for the time. It is not an easy decision for some of them to make, and even imagining that they will never gamble again can make it worse for them, most of them need all the support they can get to help them maintain the decision to give gambling some time away. If you criticize and mock them, they may nurse in the heart the mindset that gambling is impossible to stop, or even stop trying to stop gambling because you have already made them feel like they can never do it.
Obviously, I really support it according to the theme of your thread title. however, the first and most important support is: from the addict himself. if you don't have strong intentions, determination and so on. then the support given by family, relatives, friends, is only considered as a passing wind. I mean, someone who wants to recover from their addiction, whatever type it is. The first and most important thing is yourself. The question is, are they truly and sincerely willing to change. If so, intention and determination must be a package as initial tools to start fixing the addiction.
I'm interested in what you said, I'll quote it "It is not an easy decision for some of them to make, and even imagining that they will never gamble again can make it worse for them:". well, if it were easy there would be no non-profit communities, rehabilitation and so on related to gambling addiction. so, that's why it's not easy. and therefore also, an addict must support himself before getting support from his environment. whether it's family, friends, or relatives. If someone shows determination and strong intentions, support will flow automatically because that person shows their seriousness.
For me, criticism is important, but constructive criticism, not criticism that brings down. So, the point is not that someone or part of the family is criticizing. but show sincere intentions, strong determination if you want change. As for criticism, it is something that is normal and use the opposite, such as motivation, as a means of encouragement. prove it, if we can. well, something like that for me personally.