Is bro in another country? I feel like they could travel to meet up on a weekend or longer over the summer if its in Japan.
The longest train ride would be 12 hours and likely their distance would be less than half that
https://allabout-japan.com/en/article/2775/
I used to do 14+ hour straight shot car drives in my 20s and that wasn't even for kitty time
Traveling 6 hours or longer is absolutely killing, you have barely few hours left given time for travelling both ways, and the travelling one would be pretty tired. They could only meet on the those weekend when they both have whole same day free and the same one, and Japanese schoolkids have a lot of homework and stuff, not really much of a free time, especially once they start preparing for college exams. And sure, they could meet for longer over summer, but that's not much different than them being in different country at that point - at least here in European Union there is probably not much difference.
And your 14+ hours seems like hell and would destroy weekend time completely along with any pleasure from it, I think you're just an exception if you were fine with that.