1. Talk to them and don't leave their side for too long, show them some love and make sure they don't have anything to do with gambling ever again, be soft and gentle with them.
Fyi, there's a different level of addiction, if it is easy to cure them by giving advice, maybe there is no addict in the world, but it is not that easy especially if the person has reached the worst case level of addiction, they can no longer be taught or cured only through counseling because the only thing that can help them is the guidance of the family and intensive observation from medical experts. Maybe you will understand better what the purpose of psychiatrists or psychologists in the world is when you have encountered an acquaintance or relative who ended up being addicted.
I have come to realise that people only complain about gambling addiction of someone close to them only when they begin to see and feel the negative impacts of that person's lifestyle. I have seen quite a good number of addicted gamblers who have been very lucky to earn big consecutively from gambling instead of losing. Families and friends flock around them and get as much financial benefits they can get. These are thesame people that would advice or even disassociate themselves from the addict if he/she was always getting involved in troubles.
Families and friends have a lot of roles to play in ensuring that those around them are safe. First, they need to have an open mind towards gambling. They do not need to condemn gambling so bad that anyone who eventually finds interest in gambling begins to gamble in secret, this will make it difficult to help the gambler when need arises. Every advice given to a gambler goes a long way in shaping the life of that gambler. Whether a gambler is doing well or not, Families should always speak up and do something whenever they find something fishy. Before bringing in third parties (psychiatrists or psychologists), the loved ones have a lot of roles to play.