Simple temporary solution. Put teens over age 15 into vocational programs and English lessons. Then, if they choose, they can continue their academic education as adults. Or they can choose to get a job with their vocational and English speaking skills.
FWIW, how do we know how the heck old they are? I don’t care. They shouldn’t be here in the first place. As for spending public money on them, nope. If they want educating, or any other public bennies, then they can go back home and get in line.