What Sea said.
Expanding on the purpose of misbehavior , once the goal is established, and where on that list our young sorcerer falls, then I would help them find a healthy substitute. OK, easier said than done. But be clever, play the shrink, be patient. Let them discover their answer - the ah ha moment imprints on the mind much deeper because it displays as self revelatory.
Other options are available, but people have a habit of doubling down on stupid when, for example..... being scared straight. . Or called out on their true motives. Or, and in this case especially, and the damage it can do to self and others ; treating the matter lightly. Granted, Debi isn't doing that, but those around our young sourcer may, and drive them further along into that continum of 4 goals of misbehavior.