Re: Lazy eye?
There is no cure for lazy eye. However some doctors might suggest going for a little operation on the eye when the person is at least 18 or over. But they will tell you that after the operation the patient will get better but (nobody can say how much time as it could be different for everyone) in some time the problem might come back.
I think your family should take one very important thing into consideration at this time as y our sister enters teenage, to support and help her deal with it especially because she's a girl and this might affect her self-confidence if she's not given the right support from elders.