Hi, I feel your pain. Currently going through it with one of mine. Yes, it is worth him sitting the exams, they are a good experience. Is money an issue? If not, could you increase the tuition hours? Is he on medication? I think that can be a game-changer. How many weeks til the exams start? (Ours start tomorrow - IB). Drive and motivation will prob increase the closer the exams get.
He is likely to have organisational and motivation difficulties - can you incentivise him, for each hour of revision he does? (I am rewarding each hour of revision with £1! I think far better to reward / incentivise the revision / effort than the results). Maybe put a revision timetable together with him? He is likely to struggle to get going, and will need accountability. Helping them to identify what they should revise and how can also get over the block some have.
Body doubling can really help. For us, in practice, it means my dc does revision in the kitchen, and I stay quietly in the room, doing my own thing, but present. It is also helpful as when there is a concept that has suddenly fallen into place, my CS likes to explain it to me (a way of reinforcing it).
I am encouraging my dc to think about these exams as a ‘supermarket trolley dash’ - very much the aim is to pick up as many marks as possible, and hopefully attempting each question (in some way), but not wasting time in questions that are impossible (leave them and move on).
There are lots of resources out there (lots of videos on you-tube), and some good ones that do walk-throughs of past papers, or tops / strategies for how to answer a 10-mark question etc.
Also look at encouraging some physical activity - the aim is to try and get a dopamine hit, then the brain works a bit better. Exercise can give a dopamine hit (even just kicking a ball around in the garden!). Sadly, dark chocolate can give a dopamine hit too, (and caffeine), so stocking up in dark chocolate and periodically posting them into the mouth can help. Strong mints can also perk up the system. Good music can help with focus as well (weirdly).
I’m just hoping mine gets what they need to, to move onto the next stage.
I will say, though - that sometimes it can be early 20s when things kick into place for a yp with adhd (or similar), so if things dont quite go how he / you want this summer, dont despair, as things could really change for him over the next few years, and maybe he will revisit things then. Good luck to us all!!!