Somebody mentioned the idea of him going to a high school in Tokyo... Can you imagine the arrangement their families would make for that? I figure they'd expect them to live together, since the families are so close-knit. Now what a way to spend your final school years, eh? Living with the person you love? That'd be quite something.
Suffice to say, there are compromises that can be made for things to work out better. Not just the video call suggestion, but different school choices for each of them. It's not like stories haven't involved a young person moving from the country side to the city to attend high school. There'd just be even more of a reason to do it in this case than the usual excuse of just wanting to study in the big city.
Sure, the option of moving with her means he'd leave behind his whole family that he's started to appreciate more, but... kids have to leave the nest at some point, yeah? And this would be for love, and potentially his future. What if he could get involved in national sports organizations while in Tokyo, if that's really what he wants to do, professionally?