If I were the child's mother, of course I would be very angry because he dared to act unexpectedly and was very reckless in stealing and gambling, even if he won a lot of money, I would still discipline the child.
It is necessary to figure out why the child stole the money, and this is very important, because there may be two reasons:
1) the child does not have enough money to be on the same level as his peers, and he just does not want to be an outsider.
2) the child is a bully and he is attracted to such actions. In this case, you need to understand more specifically and correct the moral principles of the child.
I believe that theft often occurs for the first reason.
Differences in levels in group of children will indeed have various influences on psychology and of course child who has the lowest level will try to have similarities with his friends because there is desire to get the same attention too.
There is lot of different treatment in group of children, if there is one who is at lower level, he or she will receive less good treatment and will be more likely to be pushed aside and ostracized.
Things like this are actually very unfortunate because they have caused various bad impacts that affect child psychology, but after all, we as parents can't do much other than fulfill what they need.
But in context like this it is not about levels to be equal but it has become part of gambling, he steals money to gamble and clearly this has much worse impact so it really has to be handled well.
If there is no good and firm attitude then it is possible that similar things could happen in the future, if they only steal money from us and their parents then we can still accept it, but if this becomes theft activity in another place or another person then the problem could be different.
There will be laws that regulate it and there are even bad sentiments among society and theft is one of the things that is really considered bad.