OP The school should not be predicting 8s and 9s. Very odd! This doesn’t help anyone. It only puts pressure on pupils or, for those who could achieve those grades reasonably easily, it makes them complacent.
Also, I would say (having gone through this last summer) the mocks are nothing like the real thing - mainly because they’re all crammed into two weekls with two exams per day being the norm. The real GCSEs are much more spread out and less intense, so they have time to re-focus in between subjects. DS was much calmer in the GCSEs than the mocks.
For instance, Physics was the very last mock DS did and he was exhausted and had a headache. He got the equivalent of a 5, based on that.
He was in a total flap about maths because he’s in a very academic independent and he was in the second to bottom of ten maths sets! All his friends are mathematicians basically and he always felt as if he was the odd one out. He was worried that if he didn’t get a 7, they wouldn’t let him do A-level Economics.
We had a few meltdowns, but we never talked about 8s and 9s because, to be honest, it was a new grading system so nobody really knew what to expect anyway. In the end, he got ten grade 9s and he couldn’t believe it. He said, “I got the same as all the really clever people.”
The school later revealed that they mark the mock papers down. They don’t predict anyone 8s or 9s (even though about 85% of the school’s grades are in this region) because they know this will encourage students to cruise for the last six months.
It’s very stressful, I know because you want to help them. As a pp said, six months is a long time. Maybe a tutor for a specific subjects he’s panicking about could take some pressure off you? Otherwise, just try and get him into the habit of maybe doing 9-12 study over Xmas and then go out / have something fun and relaxing planned for the afternoon. Keep reminding him that this is all just a moment in time and it will pass. Once he gets to uni he won’t even remember these grades! I always reminded DS that anyone can do a GCSE at any time - you just send in the form and you can do a retake if need be.