Wow - that sounds frustrating Blackcat!
Have you talked to the school OT? Was he making progress with the therapy?
My DS8 (also DCD) is on a wait list for school OT - we're not there yet. However we did have him assessed privately and our private OT did not recommend handwriting therapy and recommended starting typing and voice to text as soon as we could. But in our case, DS has a pretty good pencil grip. His handwriting is inconsistent - sometimes it is OK (but he often seems to 'draw' his letters rather than print). When he is tired it falls apart and I can't read it. (Although he assures me his teacher can! LOL!)