Is He Just Wanting to Control Over People?

I was also very confused because he has to know it's not real. Like, did he think that he could get her to guess a magic number that would unlock someone else's bank account? And as you alluded to, there's a period where she and her son actually gobank to bank on foot, just every bank in Brussels. I wonder if he knows it's not going to work, but wants that like anxiety and that torture for the family. Maybe. So maybe it was just for the sake of being terrible, but he did so many things for his own gain.