I’d think that with a Level 1, DC hasn’t answered most of the paper or written barely anything.
If he’s at Grammar school, he should probably be able to get L3/4 off the top of his head and by simply answering the questions.
Many people say that if a student attends school, and are reasonably intelligent, even if they do t do any work outside of the lessons, they will know enough to scrape a pass.
Thats why this sounds like someone who simply didn’t write much at all.
Op have you seen their script?
I disagree that it’s too late to change the situation. This child is probably capable of significantly more, even if they just answer all the questions. However, perhaps they have some mental health issues or want to sabotage themselves.
The question is whether they can be motivated to try for the real things and actually to answer all the questions? If they’ve given up and decided they don’t care and either won’t turn up for all the papers or just sit there and not write anything, this could be the outcome again. If that’s the case, there are underlying problems that need addressing. It really won’t be this low due to lack of understanding.