Another thought - have you found gratitude to help in this area? As the saying goes, "Someone else is praying for.... What I take for granted."
Lately that has been so very helpful to me. As with anything, take what helps, store (or ignore) the rest.
When I read about your son's reading and writing, what impressed me wasn't the errors but the fact that he's doing these things! I find the fact that he writes more endearing than the grammar and run on sentences. So many kids and adults would rather entirely avoid things they aren't good at.
It seems to me that you're doing very well, and so is he. Just in other ways than you may be expecting.
(((hugs)))