Can blind people be cured? for Ophthalmologist!?

I have a brother aged 12 ,he was born blind(there is no other blind people ever in my family and the doctors say it's not a cataract) some years ago his eyes could sense the the strong light but now he can't! I 'd like some experts to show me the causes of born blind , if his eye nerve system is out of function ! can there be a way to cure his blind ? if not ! how many years will it take until a cure come upon ! To cure my brother is my lifelong dream ,I don't want he to live in darkness! thank you kindhearted person to answer my question !