Gambling addicts need some help and unfortunately, they cannot help themselves to get out of the cycle without the help of others. It will take time because an addict will always seek what he is accustomed of but he or she needs to endure so that sooner, he can pull himself or herself together and start living normally.
Well that's right, gambling moves under their subconscious and emotions get the best of them so it's almost impossible for them to minimize any unwanted possibilities such as possibly experiencing a lot of losses. But in terms of recovery I agree with you that they need the help of others to get out of the addiction zone, they need a lot of advice from others that will allow to help change for them. But it must also be accompanied by their intention and seriousness towards this problem, if indeed they are serious then most likely this will work.
For the boy who just turned 18 years old, he might've been a responsible gambler but he is still in a risky position because at that age, he will still have some hardships weighing the situation which in turn make a bad decision in life. It's still to soon for him to take this path and it's best for him to find another hobby because he is still studying.
In fact, this activity (gambling) will be very dangerous for those who are still underage, maybe you know they are still unstable in any case and you also know that their curiosity level is very high towards anything that comes especially new things like gambling. And I would say that gambling is very risky for those who are underage because it is unlikely that they have self-control or other limits, and I don't believe that they do. Some of the things that are out of bounds might be done when they have no other options to earn money. In this case the role of parents is needed, limit all access that can make them gamble again and keep them away from bad environments.