Gambling addiction is a personal choice. If a family member has fallen into gambling addiction, we shouldn't follow their path because we could already see the consequences of it. If the whole family would fall into a gambling addiction, it could ruin not just relationships but also the way of living. The head of the family especially the parents must do everything to keep the children away from gambling addiction as early as possible.
You can't say that someone shouldn't follow them as if they will not really follow them.
If there's an influence inside the family, they will really be influenced no matter what advise you tell to them.
They're a family and they should be teaching each other what must they do, whether there is good or bad habits of gambling.