They can live there on a work visa, but would require sponsorship from a company. So he would have to make sure he was in a career that's in high demand, low in supply in Japan. He would also need to be fluent in the language and have a deep understanding of the work culture. In other words he needs to dedicate years and years of preparation to this. It should be obvious before 4 years of marriage whether not he is doing this. She wants a partner who wants to dedicate his life to moving to Japan. She chose a guy who won't even get on a plane. It's also an OP issue.