Property

Dear Sir/Madam,  We are 2 sisters and 1 brother. Father before his death written a will in which he said my mother can not sell his property . After her death property can be sell and equal share can be given to all 3 of us . But now my brother want to sell the property and pushing my mother to do so. Is she can sell the property now . Can she do it without taking consent from both the daugthers ?