So, ordinarily an overstay of more than 6 months but less that a year on the VWP will produce the following consequences: lifetime bar from using the VWP and 3-year bar from entering the US. Whether the fact he is a minor will have any bearing....I do not know. Certainly those who enter without inspection do not start to run up an illegal presence until they turn 18.

Regardless, they're probably not going to issue a B2 since he clearly has immigrant intent.

So you need to start the immigrant visa process, possibly with an appeal to overcome the bar. Given the blotted history, you will need a US immigration attorney. This is normally a DIY job....but not now you've got complications. Expect it take a year or more before he gets the immigrant visa to travel.

AILA's Immigration Lawyer Search

__________________
Undermine their pompous authority, reject their moral standards, make anarchy and disorder your trademarks. Cause as much chaos and disruption as possible but don’t let them take you ALIVE. - Sid Vicious