From what I know, most of the time parents feel that the situation is shameful so they avoid exposing the problem. They leave the problem there and never ask for help to a psychologist for their kid. From what I saw, here in Japan appearance (such as a perfect family, career etc) come first...
About school, if I remember correctly, in Japan is compulsory until middle school. Also, regarding home schooling, sadly it's not a practice done in Japan. I had a friend from Sweden who had lots of problems with the Japanese immigration to have her home schooled years registered as official... I don't get it but it's just something they don't do and generally not acknowledge (￣∇￣")
yeesh... thats a big YIKES
erm you can totally drop out of school with becoming a NEET. INTRODUCING HOMESCHOOL. I don't understand how these kids are supposedly able to just drop out and there parents just deal with it.