We currently homeschool, but I'm curious what types of accommodations dyslexic children typically get in traditional schools. I know I should take a "can't hurt, might help" attitude, but I worry that if I work with him on working with this, that I could improve his function to a point where a test wouldn't recognize him dyslexic and he'd be denied the normal accommodations offered to children with dyslexia (e.g., I assume, longer time to take tests), especially if he does go to a regular school in the future. Does that make sense?
I understand what you're thinking through, and you're wise to think through all the angles here, but fwiw, this is a bit like thinking the issue through inside out. The thing you need to do is prioritize what the primary goal vs secondary goals are. With a learning challenge like dyslexia, the primary goal should be (imo) to remediate as much as possible. The accommodations a child uses are the secondary goal and they are a "moving" target, in that the accommodations needed may change with time and ability.
I have 2 2e kids, one who is dysgraphic and has an expressive language challenge, and one who has reading challenges. I'm going to use my dysgraphic ds as an example of prioritizing and the "moving target" concept re accommodations simply because he's older so we've been through a longer journey of remediation/accommodation. When he was in early elementary, right after diagnosis, there were things that he needed remediation work on (how to form letters when handwriting). We also knew he could not rely on handwriting to show his knowledge in class, but he hadn't learned how to type yet so the accommodation we used was scribing. While he was learning how to form letters (handwriting) he was also using accommodations (scribing) for other types of work. Once he had typing skills, we dropped scribing from his accommodations. Dropping scribing from his required accommodations didn't mean he wasn't dysgraphic anymore, it simply meant that with maturity/learning/instruction/etc, he had a different (and more independent) way of functioning through his accommodations.
His expressive language disorder impacted him in terms of written expression at school. When he was first diagnosed, if you gave him a set of three words he couldn't put them together in a sentence. If you asked him to write via an open-ended prompt he was completely lost. This required remediation in a big way, and that remediation took place over many years (he's still seeing an SLP for help with written expression). The accommodation and remediation he has received over the years have always been aimed at the skill set he had at each point in time. In mid-elementary school he was given repeated assignments, a large amount of prompting, very specific sets of what to do at each step, things like that. He's now moved on to where he is writing independently, doesn't need those prompts to get his thoughts out at this point, and is now working on specifics that enhance the quality of his writing. He doesn't need the same set of accommodations now (middle school) that he did when he was in 3rd/4th grade.
For both of my 2e kids, the most helpful thing (imo) that we've done were the comprehensive evals that helped us understand what the root issue was rather than relying on my observations. The evals also came with recommendations for remediation and accommodations. As a parent, you are going to be the person who ultimately knows your child best and sees the broad functioning across environments, and because you are the person who is most invested in your child you're going to be the person who researches and thinks everything through - but having the insight from a private professional who's seen lots of children really helped me get started on a clear path to remediation and accommodation. And I would also add that between my 2 kiddos, my dysgraphic ds has the more significant (in terms of magnitude) challenge, yet it is my dd with the reading challenge that has been much more difficult to remediate - I think because there are so many different methods of reading help advertised and debated, and also because she's not a "classic" case of dyslexia - she's basically dyslexic with a bit of a twist.
Your ds is still really young, but I suspect it might still be helpful to consider getting a dyslexia eval.
Re typical accommodations that children with dyslexia are given in school - you can probably find a list of "typical" accommodations on either your state's sped website or your school district's website. In our state, these are the accommodations that are typically "easy to get" when you have a diagnosis, simply because they are either easy for the schools to offer or they are considered standard for the disability. Extended time is the *last* accommodation I'd worry about getting at a public school simply because it's the first accommodation (in our experience) that's offered up for any type of challenge. A child with dyslexia may need other accommodations - for instance, my dd in early elementary, needed to have test questions/instructions read to her for her to understand them correctly. She knew how to work the problems (on a math test, for example) but she would read a short-sentence word problem and interpret in entirely incorrectly because she wasn't reading short words correctly. This was pretty obvious when we had her read out loud to us. Is it typical for dyslexic children? I don't know (I suspect it might be). But the key isn't "what is typically offered", the key is "what does this child need" to be able to show her knowledge.
When your ds returns to public school (or has to take state testing etc), he will most likely need some type of accommodations (no matter where he is at in his reading ability). The thing is - you come up with the list of accommodations based on his needs at that point in time. You'll have to have an official diagnosis, whether it's private or through the schools. So that's how accommodations work.
But back to my original point (sorry this is a bit rambly).... the primary goal is to remediate what you can, and as early as possible. It took us quite a few years to get a good understanding of what was going on with my dd and reading, and she was not only not reading during that time, she was losing ground across the board in school because of her reading struggles, as well as developing a sincere hatred of reading. My ds wasn't diagnosed until 2nd grade, after two years of developing extreme anxiety over schoolwork. I would much rather have known as much as I could have about their challenges much earlier, and in hindsight there were some very definite signs. You're way ahead of where I was with my ds by simply recognizing that things don't seem quite right where your ds is now. So I would strongly recommend looking for an eval in helping understand what direction to take for remediation, focus on that remediation, and then look at necessary accommodations.
Best wishes,
polarbear