Procedure for making gift deed

Hi,

     Our father passed away last month. My Brother and I are the legal heirs.

My brother was the nominee in all my fathers Bank accounts and he has already received  in his account. 

I wish to relinquish my claim on this money that my Brother has received as nominee.

Do I simply give it in writing to my Brother or do I have create a gift deed on Stamp paper. Does the same need to be registered also ?

Thanks,

Shanti