SIR CAN A SON CHANGE HIS FATHER NAME

Your father may change "his" name but you cannot change it. 

What ever be the name your morther will identify your father

MY DOCUMENT NAME SUNIL CHOUDHARY BUT MY FATHER DOCUMENT NAME SUNIL KUMAR.
MY ALL CERTIFICATE CONTAIN MY F ATHER NAME SUNIL CHOUDHARY FROM CLASS 1ST TO GRADUATION.

SUNIL CHOWDHARY/ SUNIL KUMAR WHICH  IS YOUR NAME OR YOUR FATHER'S NAME?

Your name and surname once recorded and accepted continues as such. Law does not recognise whether it is your father's name, your mother's name or any other. It is just your identity for all purposes. Once you reach 18 years you can change it to any other name that you want, following due procedure. You do not have to give reason or justification for choosing a particular new name.

Your father's name in your edcuational certificates or academic documents has got nothing to do with your father's name as is found in his own document.

You are not asked to produce your father's document anywhere to prove your identity.

Your identity documents should not have a different name from one another.

There is no necessary to change your father's  name in your own documents without any necessity..

There was a great cricket batsman. His name was Vijay Merchant. His father was Thackersay. As a child someone took him to school for joining. The Head Master asked for the boy's father's name. The chaperon thought that he was asked Viay's father's profession and said "Merchant". The School entered the boy's name as Viay Merchant. In cricket history the name Vijay Merchant is famous even now.

There was a boy named Satyakama. He was poor and was son of a s*x-worker named Jabala. He wanted to learn the Vedas and went to a holy man in Varanasi. The holy man asked him what was his father's name. The boy replied "I do not know who is my father. But my mother is Jabala."  The holy man took him as his disciple. In due course the boy became a great scholar. Among other works, he is author of an Upanishad called Jabalopanishad.

A name is just a name for identity. You are the author of your own name and no one can dispute that. I do not think that anyone will be taken to court just because his name does not contain his father's name or his father's name is pronounced wrongly.  I doubt that you can get a judgement.

There is no law in our country as to how a person ought to be named or what his surname ought to be. As a legal major, you can change your name following the due procedure. However, all such changes would be merely cosmetic. 

The Supreme Court  has  discussed the issue comprehensively  in the cases of Kabir Jaiswal v. Union of India & Ors. and Jigya Yadav vs. C.B.S.E. LL 2021 SC 264