When we talk about minors not being allowed to gamble, it's a general rule everywhere, not just in some countries, so if a child who is below 18 years has been gambling without the knowledge of the parent and he or she happensto win an amount which requires advanced KYC to be passed, if the child uses his real ID card, it will be noticed that he's not yet of age.
As a parent to the child, can you allow the child to use your details to pass KYC verification, if asked? And if you do that, does it also mean that you are supporting underage gambling?
This is a tough one. On one hand, if the win is big enough and it could help the family it is hard to turn down free money. On the other hand, it would be teaching your child a horrible lesson. I would probably tell them no and ban them from the internet for a period of time, but if my family really needed the money, it would be difficult to turn it away. Maybe I would withdraw the funds, close the account and then let it build up in an account and give them to him/her on their wedding day.