Because we dont know the medical illness then its hard to comment. I think its entirely within the lecturers discretion whether to help you or not. They arent allowed to discriminate against you, but for example if you had learning difficulties, then am not sure they have to become your personal student. At some level you will be expected to go and do your own research.
If the lecturer is stupid as you claim and there are fundamental errors in the notes, then you should politely point them out. My thoughts are that your other class mates will also have spotted such errors and raised it with the lecturer, who would then correct it for everyone. Never had a problem with any of my lecturers, so just ask nicely, be concise and on point rather than demanding. I tended to go in person.
What about your course mates- can you confirm it with them, surely you are friendly enough with one of them who is reasonably on top and can explain it to you?