I think it more likely that the stepmom is just bad with money. Either "can't budget" or "fails to keep track of cash," and she doesn't want to come out and admit it. (Especially if she is worse with money than when she was younger and the numbers were easier to see and the bills didn't stick together and there was more left after paying for pizza delivery.) Her "evidence" may well be that she has less cash than she expects. And that the young adult she doesn't quite trust has access to the drawer where she keeps her cash.
no subject
I think it more likely that the stepmom is just bad with money. Either "can't budget" or "fails to keep track of cash," and she doesn't want to come out and admit it. (Especially if she is worse with money than when she was younger and the numbers were easier to see and the bills didn't stick together and there was more left after paying for pizza delivery.) Her "evidence" may well be that she has less cash than she expects. And that the young adult she doesn't quite trust has access to the drawer where she keeps her cash.