If, as hypothesized, the child was already behind in social aptitude, then completely exempting him from the world of children and fast tracking to adulthood is hardly the solution.

Why not? I don’t think children really grow from getting bullied. If anything he is learning earlier how to deal with adults, a skill that is useful for your entire life. Having to deal with teenagers isn’t really a problem that comes back later in life unless you decide to become a teacher or parent.