Thank you again for the responses.
The child left school formally at 16. The child has not been in education or training or employment since then. There are reasons why this is very much my business, but I do not wish to discuss those at the moment. I am asking for opinions because I am confused. I had thought it was not legal to claim either CTC or CB if a child was over 16, was not in education or training or registered with a careers service. I had been advising the person claiming CB CTC that this was the case and the claim needed to end. The child is 18.
It does seem, however, that there is some confusion with respect to when a child formally leaves education and exactly how the CB CTC system works, so it is reassuring that I am not alone in this.
I have tried to access figures for young people aged 16-18 who are NEET. However, this has been difficult for me. However 808,000 young people aged 16-24 were not in education, employment or training in the year 2018.
There are a lot of reasons for this and most young people between 16 and 18 would not be able to claim benefits in their own right. My assumption was that CB and CTC would cease for these young people, thus putting more pressure on parents/guardians to ensure the YP secured some form of education or training (even if it was only figure massaging Mickey Mouse courses).
However, I know the young person in question never enrolled in or engaged in any type of education or training. Now the YP is 18 s/he could and perhaps should claim benefits, which would, at least, put the YP back into the system. If/when this happens, if the person claiming the benefit is still in receipt of it, then the discrepancy will show.
Obviously, the benefits may simply cease in September and the YP will either remain unfunded and unseen or start claiming UC or its equivalent (or better still, gain some form of employment or training). However, the very fact that this YP (and perhaps many others) can simply not engage in society for two or more years and no agency, or authority is aware of this is frightening.