Responses

In Asian countries such as Japan, the older person usually pays for the younger ones. It’s like a sense of responsibility or duty they feel. Especially if the younger one is someone they know. In this case Hatano is the mc’s younger brother’s friend, someone who comes to their house often. So for the mc he is like a younger brother to him making the mc feel a sense of duty to act as Hatano’s elder brother. So basically it’s like a cultural thing. I hope this makes sense, I’m not very good at explaining.
HELLO?? WHY DID HE PAID FOR HIM?? THAT JUST KEEP THE FLAG THERE! HE MUST'VE ACT AS AN ASSHOLE OR SOMETHING TO KEEP AWAY HATANTO ヽ(`Д´)ノ HE'S TOO OUT OF CHARACTER