I could see another Chinese team taking a chance and signing him for $700-1.2, but would be shocked if he played in Europe. Euro ball is, as a whole, too advanced and physical for an 18yo. More importantly, coaches aren't there to develop HS kids, at least not at the top level of each country and Euroleague play. Perhaps he would go to Europe and play in a 2nd tier developmental league/in the ULEB Eurocup level games, but that would come with significantly less money.
Hell, even Chinese teams at the top level aren't there to develop 18yo straight outta high school players.
Coaches in international basketball at the top levels are coaching for the immediate. If they don't perform now, they and often times US players on the team and let go. Emmanuel Mudiay in China this past season is a great example- he gets hurt and doesn't play for 2+ months. And the team was going to bring in someone to take his minutes even before his injury, and even though he was playing well all thing considered. Mudiay was making mistakes that come from learning on the job and the team doesn't have time for that.
If he doesn't go to college, he needs to toss his name in the DLeague draft, make $20K plus per diem and housing, and work hard.
He will be playing in front of NBA scouts and coaches against significantly better competition than college, and there will be plenty of tape for teams to know his abilities. Assuming he is legit, on draft day he will be more prepared than others to make an impact in the NBA.