They don't dx dyslexia in many non English speaking countries.
Especially countries with very phonetically regular languages.
However of course, doesn't mean it doesn't exist :)
I live in hope that what really happens in those countries is that instead of labelling the symptoms of being unable to read 'dyslexia', because they don't have that label, they actually find out why the child can't read and address that.....
It really is much, much easier to learn a phonetically regular languages. So kids do struggle less.
Anyway, I agree with her, in that I don't think dyslexia exists, or is a helpful label. :) Something (probably lots of things actually) are stopping your child from learning, and a label of dyslexia won't help your child read at all.
A thorough eye test and a thorough hearing test and a look at retained reflexes and other neurodevelopment markers and a vitamin deficiency test would be a lot more helpful.