I had some experience with being a big brother. But Inari was very different from Harry. For one, we had grown up together, while I (finally) met Harry when were both adults. Plus, Harry was an insanely powerful honest-to-god wizard and I was a freaking vampire (not that I ever wasnt, but Inari hadn't known that).
So I was, understandably, a bit wary of having a younger brother.
Looking back, on all my worries and concerns and secret fears, wondering if everything could manage to turn out okay, I want to go back and say; It will.