oral will

My dad expired 10 years ago.he is survived by my mother and three sons (including me).due to lack of knowledge he did not make any will.my both the elder brothers left the house long before my dad's death.now, my dad purchased two flats on loan.he told my mother and other relatives that he wished to gift one flat to me during my marriage. Ever since my dads death, I have been taking care of my mother and both the houses.but now, suddenly my brothers have started to pester my mother to sell off both the house and give their shares.we are staying in both the houses and it wouldn't be possible for my family n my mother to leave our houses as we dont have any place to go.please help us resolve this problem. Note: our relatives and fathers friends are willing to sign d affidavits affirming his last wish of gifting one flat to me.