Ancestral Agricultural Land

My father died in 2000 he had around 1.8 acre of ancestral agri land on his name. but later his name got removed from the land. Background - He lost both of his parents in childhood hence for education purpose he was away from village, he later got employed in MTNL as engineer and got disconnected completely with his village. His cousin got his agri land transferred on his name in year 1985 by writing down on simple plane and not on any legal document, that my father is in Mumbai for job and hence do not have interest in agriculture hence want to transfer the land to my cousin. and then my father's name got removed from 7-12 revenue document by Talathi(Patwari). My Father was not married that time. We all were staying in mumbai - thane till his death, with almost none of contact with village. My father told us he never gave consent for such transfer or made any such paper note or made any signature. Therefore he never initiated such transfer, but now didn't want to ruin the family relations by taking up the matter. HIs Signature and Handwriting is highly contentious. Can the said agri land be transferred to my mothers name now ?