Gambling addiction cause lots of people to do the unthinkable and if they are not willing to change their ways themselves or make their kind to then all efforts made towards changing them will simply be wasted.
That is how people that are gambling is. Some will change their mind when they know that gambling addiction will destroy their lives. Such people do not need any rehabilitation at all. But there some people that may still think they can make money from gambling. If the person can listen to his family and go for rehab, this can psychologically helped the gambling addict to quit the addition as they walk on the person's mind to think of quitting.