The experts don't always get it right, I'm sure they're made plenty of mistakes just like doctors, nurses, police officers, scientists. they can't determining for certain that it could work for this person.
cochlear implant does not guarantee the ability for everyone to hear. It all depends on how it'll pick up the responds of sounds.
I've know some people who are implanted didn't get expectations lot out of cochlear implant but they got what they want to hear, like for example music.
