Family subscription

I know Family Sharing is available in other countries such as Germany and France but I don't have a list of which ones exactly. The people on this forum are just users like you and we don't know anything more about the status of family Sharing in Korea than you do, sorry. You will know as soon as we will (probably you will know sooner since I don't routinely check for Korea) if it will be available in your country. You can also make your desires know to Apple here:

Click on this link for Apple products feedback links --> Product Feedback - Apple

Apple may not respond but your comment will be read.

Upon re-reading I see you may be talking about a family with members in two different Koreas. Apple does not allow Family Sharing when people are in different countries. Again they do not say why but often licensing laws differ between countries and it would incredibly complicated to keep track of what is licensed where.