Help in prison?

I can’t think of a show that has left me with more questions, so here goes: 1) they referred to where Jamie is as a training center. Is that just another name for a juvenile prison? 2) I have read one post here that speculates that Jamie could be released by 21 and be a functioning member of society if he received the proper counseling and rehabilitation. Do they receive that kind of counseling and rehabilitation in these centers in the UK? To be honest, I don’t know what happens in these centers in the US. I actually have a friend who works in one, so I am going to ask!