Hi op, my son struggles with handwriting (he is now 11 and your sons is much much clearer!)
his school referred him for an occupational therapy assessment, it was brilliant. They assessed his physical skills all over (walking, hopping, threading things through things, tying laces etc) and identified his weak areas.
in my sons case he is hyper mobile and meets many characteristics of dyspraxia and ADHD.
once the occ therapist had identified his struggles it was amazing the amount of things she had to offer to help him. this was in about year 3 and since then he
- sits on a wobble cushion, because he needs that sensory feedback and balancing on the cushion gives him that so that his hands and mind can focus on the task
- has a writing slope, which better supports his arm so his letters can be formed more correctly more often and spaced well. When his arm is tired he is more likely to do letters backward etc as he’s fatigued
- uses stabilo easy grip pens and butterfly grips on his pencils, which help him have the right hand shape for decent writing
- uses a laptop for any work that doesn’t need handwriting. This was difficult at first as like your son (and any child of their age) he found typing just as hard as writing, but there are some brilliant online programmes that schools can access that turn learning touch typing into a game. He got the hang of it within a year and now types very fast and precisely.
there is a lot of crossover between his writing performance and traits of ADHD - it’s all about propioception (probably spelled wrong, but their awareness and control of their body in space) and then lack of focus on precision and repeating work to correct mistakes.
my son is bright - he’s now in grammar school, but I’ve been told his handwriting will likely never improve. Using all the tools above unlocked all the clever stuff in his brain and gave him a way to communicate it without barriers.
sorry, long post, but all this is to say if you’re worried then discuss occupational therapy with school so you can find out what the keys are to unlock it for him.
oh and look up the DASH test, an occupational therapist can do it. It’s a recognised, standardised handwriting assessment that will show where your son’s abilities lie in comparison to national averages at different ages. It is useful to have a DASH result to show exam boards if he needs extra time later.
(that’s another point, my son was offered extra time or a scribe for his SATS and 11+, as we had these assessments and results)