I wonder if a quick trial of Handwriting Without Tears would be helpful? I don't know if an older child would benefit but it would probably ease your concerns and certainly address that basic handwriting instruction issue. FWIW DD hated it - she said "for me it's most definitely writing WITH tears" but people swear by it. Maybe someone here knows if there is a home version worth trying.
Has your district ruled out dysgraphia? It seems remedial instruction from an OT to address your concerns would make sense and not be terribly time consuming or use too much in the way of resources. I just ran the question by DD and she feels strongly they have to determine if he's actually dysgraphic. "If he's dysgraphic it's not going to make any difference for him." Just a bit of btdt advice from one 2e kid to another...
