Procedure in case brothers trying to claim property given by mother

Dear sir/Madam We are 5 brother and sisters from our parents. 2 brother and 3 sisters, I am the youngest one. My parents were with me throughout their life. We have a house build up by my father registry was in his name, he expired in 2003. Thereafter mother was with me till 1 oct 2017. She also expired recently. My elder brother sisters all gave a written concent that they don't want any share in the property before mother’s death on a stamp paper which was not registered. But my mother wrote a will that the house will be given to me after her death ( which was registed). Now just after my mothers death my brother is demanding his share. Plz suggest me about the legal safeguards. I served my mother and father throughout their life. Although my who is a govt. servant is going to retire next year resides in another city, having his own flat there, he will get pension and all facilities provided by govt. I the contary i am working in a pvt school having very nominal salary.