Originally Posted by benny
You've given me tons to look at: convergence insufficiency, non-sequential learner, visual spacial learner, motor planning.
if it helps, non-sequential = spatial, at least according to Silverman. For motor planning I'd look at OT for SPD. And of course for convergence insufficiency, see www.covd.org for some info and an optometrist who does vision therapy. Also, ocular motor problems are another subset of SPD.

Has he tried keyboarding instead of writing? Good luck!