Prisons do not rehabilitate. That exists in TV but the 'enlightened' programs which were in effect for decades ended in the seventies and eighties. Punishment through incarceration is the current program not rehabilitation or training.
You think prisons are supposed to rehabilitate and retrain but that is a myth based on the way we used to be in this country.
Many myths exist based on how we think things are because of the way they once were. Remember when they needed a warrant to wiretap? Sounds quaint doesn't when compared to the reality that we have these days. Our constitutional rights pre-patriot act that were demoted to privileges post the patriot act? The corporate coup compared to democracy? Citizens United? Trade pacts vs national laws.
Prisons punish not rehabilitate but apparently there is some attempt to control the more unjust punishment due to the strenuous efforts of advocates to limit unlimited punishment...at least for a kid.
No chance of a parole is usually a cost saving measure BTW as is limiting appeals etc.