If the all class plays Fortnite and that is the only way they get socialized, his parents should consider moving him to another school. Many kids don't play this kind of stuff and actually prefer hanging out.

This kind of approach is also invalid. So what everyone plays Fortnite? There are many places to get socialized with other kids. The kid likes basketball? Sign him up to a basketball team; he likes to play music? Sign him to some band; etc. Kids shouldn't surrender to peer pressure.

I agree schools are also a problem, but not the main problem.

Yes, it's quite easy to change to the school with the "correctly"-behaved children in the USA. It won't solve any of the other structural issues that grade-separation causes, but at least this one has an easy answer!