It is better to use Hearing Aid as-here is the website that is helpful regarding this matter.http://www.hiddenhearing.ie/
I didn't know that i posted the question in allergy.
She consulted the doctor 6 years back or even more and the doctor told her that it has been since her childhood and cannot be treated.
So i want to ask you that what is the reason behind.
What precautions should i take care so that i protect her other ear.?
Is there any possibility that her other ear can also have hearing loss.?
You have not told "us" anything that would help us even venture a guess.
Are you sure the hearing loss can not be treated?
Clearly, with the loss of hearing in one ear protecting the other is even more important.
Given you posted your question in "allergy" are you saying the hearing loss has been diagnosed as caused by an allergic reaction? If not, there are better communities you might post this question in, along with more information on causes and concerns.