I love this. You worked so hard, and thought outside of the box, so much! As a public school special education teacher, this is the kind of thing I desperately WANT to do for all of my students, but I'm constrained by certain unchangeable parts of public school.... schedules... other teachers who don't get it or don't want to think outside the box... curriculums already bought for me... I could go on. I do as much as I can to be as flexible as a homeschool mom, but being in public school has limits.
I feel sure that your son has watched you be creative and resourceful, and absorbed the fantastic life skill of encountering an obstacle, thinking creatively, and working around it and moving on. That kind of flexible mindset (dare I say the overused phrase, growth mindset) is way more important than most academic skills, unless a person wants to go on to more academic education.
I also feel certain that your son will learn new skills when he needs them. Take grammar, for instance... he's going to be really motivated to write a good email to his boss or a client... and he's going to work hard to make sure it sounds right. Or, say he's going to a job in a new place. He's going to learn all about it, how to get there, etc. He may get more interested in other things, like watching the news, and learn something like geography from that.
You got a dyslexic kid to read well, do basic math, and also be a hard worker and all-around awesome kid? That is amazing and something to celebrate big time!