Diagnosis & Treatment for ADHD teen near Toyama?

My husband was diagnosed recently while in Australia (he works there part time) and will get meds on his next trip back in a couple of weeks.

The problem is that I’m pretty sure my son has ADHD too and he’s really struggling with day-to-day tasks – and appears to be going backwards with his capacity to complete his school work.

This isn’t helping him cope with the transition, and he’s supposed to start school locally this month (middle school).

To complicate things – our long-term visa and work situation is still being processed, we purchased a house and are living here, but in the meantime we are on a short term visa and only have travel insurance.

We also only have N5 Japanese, if that. We’re getting a lot of support in our small town from local government, the migration office and our neighbours who seem delighted that a random Australian family has chosen to make their small town home – they moving mountains to get our kids into school etc. But I get the sense that ADHD is a bit of a mystery here, at least in the regions.

Any info, advice or tips for the best and fastest way to get diagnosis and treatment would be much appreciated.

Edit: I’m already looking at the international mental health practitioner database and am aware about the restrictions around Ritalin etc in Japan