Advice or direction appreciated

Does anyone have experience importing an immune compromised cat? I have been thinking about moving to Japan, but my cat has a condition called pemphigus and it results in him not being able to be vaccinated. His immune system will start to attack his body and it is a deadly series of events. My other two cats and my dog get their regular vaccinations and all my cats are indoors 24/7. If my immune compromised cat cannot come with us or is in 6 month quarantine, we may as well just find a different country to consider… his health and happiness is a priority to me since I nursed him from two weeks old. Would something like an immigration lawyer help us? Or something similar?

Edit: I’ve read over the guidelines that are posted here and on the website but could not find anything about a circumstance like this.

by katkatbar_