Answer: Homeschooling there is not an international standard.
Is not a form accepted of education in a general aspect, the countries have the power to decide about what homeschooling can be done.
Homeschooling vary in many countries, so depends of the country. In some countries homeschooling is completely illegal and seen as an abandonment of the children. Homeschooling may be a option, but for that much has to change to be confirmed, with international serious rules.