Responses
Late reply... he said "I want to eat delicious food like this EVERY DAY!" The "every day" part is the key. He blushed because that's like basically saying he wants them to be together from now on. They both realized that he unintentionally made a confession. (And at the end they confirmed that they both felt the same.) I hope that makes sense. :)
http://www.mangago.zone/read-manga/kirei_na_onii_san_ni_horeraremashita/uu/m_chapter-6.5/pg-4/
What happens in top panel of this page?? Why does he blush??