Yes but, the grandma is the one who told her granddaughter about cochlear implant, at the begin of the movie, You'll see how she told her grand-daughter that she could hear the telephones with cochlear implant, how she could hear the birds, the wind and etc. She was the one who gave her books about cochlear implants behind the parents back, then the daughter goes home and tell her parents that she wants cochlear implant, the parents was surprised because how does she know about cochlear implant?? Her mother wanted her daughter to be 100 percent certain this is what she wants.
And her mother went with her to find information about cochlear implant as I remember the mother wanted one too. So if the mother didn't care of her daughter's wishes, she wouldn't have took her places where all cochlear implant kids go to school at, and meet other parents who have implanted children.
It was none of grandma's business to begin with, and the idea of cochlear implant was brought up by the grandma, she has no business to even discuss things like that to the grand daughter, she should be the one suggesting it to the parents not the grand daughter.