Sure, punishment is important, gotta let him know that ain't cool. But just yelling and grounding him won't fix the real problem, right? This kid's clearly got something deeper going on. Maybe he's hooked on gambling, maybe he's feeling the pressure and trying to escape in a risky way, or maybe he just saw his dad blow his paycheck on the ponies and thought it was normal.
Whatever it is, the parents gotta dig in and figure it out. Slapping a bandaid on this with punishment won't cut it. They need to talk, listen, and show some real support. Maybe get some help from a therapist or counselor, someone who can untangle this mess and get the kid back on track.
In general, stealing money from parents is the first problem that seriously hurts morally. And the second problem is that it is necessary to solve the problem with the possible dependence that is forming in the child at this moment, if he was ready to do it. You have to speak so carefully with a child that it’s like finding the key to his moral state; it’s incredibly difficult to do. But the problem must be solved, otherwise it will happen again if nothing is done.