Gamblers at their teenage, do many mistakes. But it doesn't mean they are bad. Actually sociaty always treated gamblers as suspicious and so was happen with your newbie. She wasn't sure her momey was stolen or not but suspicious mind force her to believe such thing. actually when it comes to gamblers, people are too quick to judge them without trying to reveal the trusth. Let gamblers have some time figure it out. My perception about them is that, your nephew would grow up soon with hard experience and then he'll set his mind to figure out which is good and bad for him. Until that, give him just one advice is to control himself during gambling, only stake what he can afford as he also said already
Mistakes are not only dominated by teenagers who gamble, but all gamblers will make mistakes, which is why they lose, make mistakes in analyzing, or make mistakes in thinking which use gambling as a way to increase their income. Gamblers will often make mistakes and lose money because of these mistakes
Teenagers shouldn't gamble because they are still young and don't have an income, so when they are involved in gambling at a young age, how do they finance their gambling? Asking parents will certainly not be given because no parent wants to see their child gambling.