Does your relative good in computer / internet, and also can read Chinese traditional characters?
I'm asking this, because I'm also learning Japanese in Chinese language.
However, I'm learning Japanese with a Taiwanese teacher.
He has online courses, from beginning up to N1 level.
I bought the course, and whenever I want to learn, I just opened the course and learn. Anytime, even midnight too.
And no, the course bought will not expire. If I bought last year, I still can learn the course this year or next year.
I'm learning from him because:
1. I couldn't find learning Japanese course in Chinese language over here in Singapore.
2. The course is much cheaper as compared to here (about 30% - 50% cheaper).
3. I can learn anytime I want.
4. He teaches a lot of things which typical textbook doesn't teach.
Btw, sometimes he might also do FB live, have a few questions asked by students, and explained the questions and why the answer is this and not that.... This is usually on Sunday nights, 9 pm.
Oh ya, currently he also has published 4 learning Japanese books, and seems like 2 more are also confirmed to be published.