Ok this is different. What you described can actually be an LD in which case it is not a behavioral thing but an LD that will need to be accomodated so he can learn in different ways.
https://www.understood.org/en/learni...ing-dysgraphia Hopefully this may help. My younger son had issues with those very same things. I had to stop trying to have him color or write except for tracing and forming letters to practice that way and then once he was older having him write brief answers after he would orally answer the question There are app.s to download to help. They do best with being aloud to answer questions orally or express themselves through plays they can act out and that kind of thing rather than writing stories. My son did fine with other fine motor skills including working with tiny transistors and things in a robotics class later. it also helps for them to trace with finger. In the dirt, Trace in a tray of salt or dry rice