Can anyone offer advice on pen grip please.

[TitsalinaBumSquash]

My 7 yr old DS has significant hyper mobility and is being investigated for other SEN such as ADD and SPD and dyspraxia.
At school he has had an OT recommend he sits on a gym ball to work and has a tool kit of sensory aids for him to use.

However, his own grip is and continues to be an issue. He writes as pictured below and it causes his fingers and wrists to get sore. I don't know if I can help him to correct it or just to manage it to not get so sore.
I can't get anymore supper with OT until he goes back to school.
He's in year 2 and very bright but his wiring continues to be a struggle.
Does anyone have any tips or advice please?

[sleepismysuperpower1]

would he try a pen grip on his pen/pencil? will link one below x

www.amazon.co.uk/Lenfesh-Children-Silicone-Writing-Correction/dp/B07CSZRVQH/ref=asc_df_B07CSZRVQH/?hvlocphy=1007097&linkCode=df0&psc=1&hvnetw=g&hvadid=427990402203&hvdev=c&hvtargid=pla-891789088467&hvrand=1137574008848692797&adgrpid=97823381005&tag=mumsnet&ascsubtag=mnforum-21

[TitsalinaBumSquash]

I will certainly give it a go.