should my brother sign any relinquish ??

My father hadn't yet made any Will-Deed for his self-acquired house in which I am my mother are staying. As per Hindu Succession Act 1956 , my mother, myself, and my brother are the class I heirs to my deceased father's aforesaid property. My brother orally says that I can keep this property after my mother's lifespan. But, is there any other written format (for example, relinquish, etc) in which my brother can commit himself so that later on I am not subjected to any property disputes or complex situations from my brother or from his kids ??