I mean that really depends on the world you are set in: if magic is everywhere/can heal anything someone who is blind could break immersion IF there is no good reason (he doesn't want to see for personal reasons, it's a curse and can't be removed etc.)
However if magic treatment is rare/expensive of course there would be lots of disabled people (monster attacks, accidents, diseases, etc.)
Obviously thats not the problem here(the guys just a dick) but it's something i run into a lot when designing worlds/characters: a lot of our real world problems fall apart if introduced into a magical setting.
tell that to my english teacher! we had to study that book and got to make a literary analysis! (german school btw.)