"do they have one for dyslexia?"
No, but they will catch things like your use of 's as a pluralization for a couple of words. They'll also catch your agreement in number errors. Your message is not a bad one, except for the mistakes a spelling and grammar checker would catch.
You clearly hope to influence people with your writing. I'm just saying that a message written grammatically and with proper spelling and punctuation will have a greater impact that one just dashed off. Proofreading will catch some of your errors, but careful use of spelling and grammar checkers will catch most of the rest of them. I did not see a single error in your message that could be attributed to dyslexia.
I use it when sending email, much better at speaking thank you for your counsel