MADPUPPIES2

My son 17 is moving back to the UK to attend sixth form although he has completed 12 th grade in Canada .(long story) He will be doing different subjects and the college is asking as to what level the diploma equates to. I know that it is AS level but if he hasn’t completed his final exams yet how do I prove this to them. NARIC only wants documentation when they’ve finished school by the looks of it so need advice if anyone has it please. Has anyone else gone back to sixth form and enjoyed it