Understanding spelling errors

[GrumpyMuleFan]

DS in y10 has trouble with spelling in real life, when writing.

He is dyslexic and has ADHD. His working memory is poor, but has been improving since recent ADHD diagnosis.

His English teacher despairs and is worried about GCSE as 40% of the grade will come down to spelling and punctuation (which is also appalling). In Learning Support he regularly scores 85+ on spellings. It's the same with the punctuation - he knows the theory, but can't seem to apply it.

Over the years I have spent so much time teaching him how to spell, I've just dug out a whole lot of materials and flash cards that we used to use. We've tried lots of different techniques and interventions. I find it a bit depressing looking back at all that effort and wondering what will be different this time.

We're going to focus on English over the holiday. He talks very well, in fact, he has the gift of the gab and is entertaining and engaging. None of this translates into his writing, which tbh is dull and lifeless.

Has anyone come across this with spelling/punctuation? Is there anything he can do to improve his spelling / punctuation recall and writing style?

Have you considered whether a scribe would help?

Sometimes peole with ADHD don't see the typo/spelling mistake; it can be painful to go back and check detail slowly.

SPAG is only 20% of the English GCSE marks.

In a similar position with Y10 DD - severely dyslexic, very weak working memory and ADHD. She has zero clue if she spells things wrong - often the same word will be spelt 4 different ways in a single paragraph, so even if she goes back and checks she just doesn't recognise there's an error.

To add to the fun, she's also exceptionally good at creative writing and has very high predictions for English.

But... she uses a laptop for everything and has spell check, grammarly and every other bit of software to help, and so her teachers have yet to see what happens when that is turned off.

I've contacted the SEN and English departments and asked them to take a look at the difference. Her current assignments all have correct punctuation, spelling and grammar - but the second you turn it off, you would be lucky to be able to decipher the spelling and she rarely uses punctuation.

My feeling is that we may be better just to lose the SPAG marks up front, English teacher thinks she's got a better shot at the top grades even if the examiners need to tackle her papers like a crossword puzzle.

It's pretty infuriating that they can't just be marked on the content.

Very similar situation with my DS.
For practical every day writing he types using a spell checker of uses talk to text.
He's also working through the Touch Type Read Spell programme which teaches spelling alongside touch typing, so that the spellings are"remembered" via muscle memory.
It's very boring for him but we're seeing results.

In your situation, so close to exams, I would be looking at what reasonable adjustments he can access. Have his teachers)SENCO suggested anything?