Question Summary:
in all of my documents (e.g passport, birth certificate, educational documents), my step father’s name is used as my real father’s name. Do I need to change these documents….and One more thing is that I have a half-brother (we have same mother) who doesn’t know that my mother re-married. Should I tell my half-brother that I am not his real brother.

Question Detail:

I am a male. My father and mother got divorced and my mother remarried. My real father is still alive. Recently, I came to know that claiming that my step father is my real father is a major sin. This claim can be documental or verbal.  However, in all of my documents (e.g passport, birth certificate, educational documents), my step father's name is used as my real father's name. Do I need to change these documents (how to change father's name). Will I need to change all document or will I make another document stating that name which appears in my passport/ certificates is the name of my step-father.

One more thing is that I am using my real father's surname as my middle name   and my lastname is according to my step-father's lastname. Is this naming acceptable.

Another thing, my close relatives knows that he is my step father. Relatives who are not close or friends / neighbors does not know that he is my step-father. Should I let them know. What to do if my mother or step-father or some close relative doesn't agree as they think it might hurt their feelings or they think that it will cause a social problem.  Please answer from Hanafi point of view.Please let me know whether I need to change all current document, make new document while keeping the current document, change surname, let people know that he is my step-father.  
   
One more thing is that I have a half-brother (we have same mother) who doesn't know that my mother re-married. Should I tell my half-brother that I am not his real brother.  

Does claim (in subject of email) indicate both documental  or verbal claim or just verbal claim.

Answer :

In the name of Allah, Most Gracious, Most Merciful
Assalaamu `alaykum waRahmatullahi Wabarakatoh

Allah Taala says, “Call them (adopted children) by their father’s (name); that is more just in the sight of Allah. The background to the revelation of the above verse is Rasulullah (صلى الله عليه و سلّم) adopted Zaid (RA). People used to call him Zaid ibn Muhammad. Allah Taala instructed Rasulullah (صلى الله عليه و سلّم) that adopted children be called by their father’s name. If your official documents record your step father as your father, that is incorrect. Your step father is not your father as implied in the official documents. You should change your official documents and record the correct position in them.
 
The society you live in should know your identity. You should discuss the issue with your mother and consider the most appropriate cause of action to address the issue regarding your half brother and other relations.
And Allah knows best
Wassalam
Mufti Ebrahim Desai
Darul Iftaa, Madrassah In'aamiyyah