Firstly, no amount of accommodations etc is going to make a dyslexic person a good speller, or not struggle with writing.
Disability rules usually say that "reasonable accommodations" should be made for people with disabilities. The spirit of this is that if a person cannot perform their role, then they can't, but if there is something that can be done to allow them to perform their role, then they should be enabled to do so.
Applying that principle to university, this should mean that a student should be assessed on the course criteria, but where something that is not in the criteria is stopping them from demonstrating that they've met the criteria, then they should be helped around this.
The upshot of that is that dyslexic students should not be assessed on the quality of their language unless that is a specific aim of the assessment, but where it is the specific aim, they should be assessed against the same criteria as everyone else.
So we teach molecular biology. In our exams we are testing the students knowledge and understanding of molecular biology. As long as your language is good enough to demonstrate an understanding of the material then you should get the marks, irrespective of typos, odd phrasing or places where the grammar is wrong, but the meaning is clear. If the writing is so bad that I can't tell if you understand the biology or not, then you shouldn't get the marks. One can imagine this would be different in an English Language exam.
On the other hand, molecular biologists need a certain level of language abilities to succeed, and so we have course work where the quality of the communication is assessed, but in these cases students are allowed to have their work proofread the same way someone in real life might have their reports proofread.
I am both dyslexic and dyspraxic. People who regularly read my posts will notice that I am not a good speller. But I have still been a good enough biologist to make a career of it, so I'm glad my university assessed me on my biology ability, not my writing ability.
On the other hand, my dyspraxia makes me clumsy in the lab and no amount of accommodations is ever going to make my experiments go well. So it was in my, and my employers/fields interests that I decided the lab wasn't for me, and became a computational biologist - Reasonable adjustments could be make for my writing ability, but not for my lack of manual dexterity.