My mother was married way back 30+ years ago from other man. They were separated but not legal. I mean, the man is now married with another woman and my mother met my father. They are not yet married until now. They are together for almost 25 years. However, in our NSO birth certificate, we are using my mother's surname which is the surname of her former partner. The moment we were born my mom wrote the former partner's name as our father in our birth certificate without knowing the effect of this. Maybe she was afraid because of his profession. My father couldn't do anything about it. I don't know the reason why. Later on, my biological father brought my brother in our province. My mother and father registered my brother's name using my biological father's name in his credentials until my brother graduated in high school. All credentials of my brother is using my biological father's name except in his birth certificate.
Now, my brother is in college. The university asked us to past the NSO birth certificate of my brother but the school didn't accept it because of the situation. So, we wrote a letter serves as a promissory note. We promise to give the NSO birth certificate without necessary problem before his graduation. However, until now we don't know what to do for this situation. I felt so pity to my brother when he talked about this. My parents did not do anything as of now. They were all afraid for the consequence. Some people advise us to file an adoption. My father may adopt my brother. Is it possible? Is there any legal way to make my brother's surname change as soon as possible because he is now in 4th year college?
Please help me. Your reply is highly appreciated.