According to the law, family members of third-country citizens entering the country are: spouses; the other spouse or partner with whom a third-country national has a cohabitation agreement in Greece; the direct unmarried descendants of the spouses, who are under the age of 21; the direct relatives of the spouses in the ascending line. According to the above, there is no exemption for children above 24 years old, but your adult son could be the investor and property owner, and his parents could be granted resident permits as direct family through him.
