Wife's right

My father got ancestral property in 1958 from my grand father after execution of relinquishment right by my father in favour of grand-father / mother and uncles. In 1984 father executed memorandum where in one share given to me, one to my elder brother and rest residual property is kept by himself ( father) along with mother, of said property received by my father in 1958. Document of 1984 is unregistered while document of 1958 is registered one. In document of 1984 there was stipulation that my mother will not sell, mortgage her share in said property during life time of father without written consent of my father. Subsequently in 2020 my elder brother got gifted share of mother's property in his favour. My query is 1) Whether my mother is eligible / entitle for property executed in 1984. 2) Unregistered document of partition titled as memorandum is legal. 3) Can mother gift property in spite of stipulation executed in document of 1984 that written consent of father is mandatory and father is still alive.