DC aged 15 refuses to revise

[RefusingRevisionGCSE]

HellAny tips on how to approach this? DC is 15, states they are non-gender binary, is ASD diagnosed - Asperger's syndrome. Says they have "brain fog" and can't revise therefore does very little, Over the 2 week Christmas period admitted they did 1hour - said they could not concentrate. Gets very upset when challenged on it. Wants to see GP to ask them to fix the brain fog. Says they read a question on the exam paper 8 times but it still didn't go in.

GCSE mocks results are coming in and it's not looking good.

Now, I know forcing someone to revise isn't the answer, they need to want to do it to be able to take the info in.

What am I missing to make it better for them? Any tips/tricks?

I'm also posting on the ASD boards here for advice from the Asperger's perspective.

Thanks. Ds year 10 but has Eng lang early [his lowest mock mark but still ok]. Not 100% happy he is doing it early but school being a pain about it.
Think may need something like Seneca to structure him on the bits he finds 'boring'...
AQA board.

Irritatingly, will have to push from home with English as push not seeming to come from school.
Managed to get ds to look at Seneca Eng Lang tonight. A brief look but he conceded it may be helpful. He liked it for science so not new to the free version.
Pissed off they expect him to do it early as suspect predicted grade lower for that reason. Ds will have to pull his finger out...
Will also email the school and be 'that sort of parent' again...