Is she actually scolding the kid for selling stuff that doesn't belong to him? He's literally disabled and living on the streets, and it's the only way he can earn money to pay for his parents' medicine.
But after hearing his story, instead of showing sympathy, all she said is "I'm pretty sure selling the property of others is a crime." Like wtf else do you want him to do? The original owner lost the book, it's not like the boy can or should go looking for them to return it. He might as well sell it to try and survive.
Plus it's so hypocritical of her to chide him about stealing stuff when she's literally been stealing metal to feed Ray. And what she's doing is technically WORSE because she's not using lost items, she's literally just taking things that people use and need every day--and she's not even poor, so it's not like she needs to be stealing it to survive. What the fuck, MC.