I'm not sure what to say here.
Both my boys are dyslexic. They will never be straight A students. Their spelling and typos will always be a problem.
They can't read dense text if it is boring, but they can if it interests them.
My oldest is at a very good college, reading a ton of material and writing lengthy assignments. He will get B's and C's. (hopefully) If he fails out, he will come home, go to MD and take a lighter (3-4 classes) course load. He will never follow the path of his friends. It might take 5 or 6 years to graduate, idk. Things will always be harder. Somehow, he is a leader among his group, he has amazing social skills and can do good enough to hang with great students.
My youngest is still in HS. He gets A's and B's and might be getting a C this year (junior). He will go to an SEC type college. He is good at math so probably will do accounting or finance. Probably won't be great, ever at writing papers. He will probably exceed at Excel spreadsheets.
I am dyslexic, I got mostly B's and C's in college. I have a good job in IT.
I want to give you hope but I don't want to be unrealistic. Keep up with the tutor, be realistic about what is a "good" grade. Stay positive, give them love and support.
There are very few things (besides catastrophic illnesses and injuries) more challenging than being dyslexic.