Whether Second Wife's son have rights in ancestral Property

My father have two wives. I’m his second wife’s only one son. His first wife have one son and one married daughter. My father got 9 acres of agri land and 16 cents with house property from his ancestral property and he purchased 4 acres of agri land and he sold that 4 acres for Rs. 1,00,000/- while we was minor, he didnot make any deposits or assets for anyone. His first wife got 10 acres of agri land from her father, they sold that agri land and finally they came to my father’s property. My father splitted 16 cents of house property into two, one for his first wife and another for my father and me. My mother left me and my father due to some reasons. My brother planned to sell father’s 6 acres of agri land inorder to meet the marriage expenses for my sister and my father agreed to sell 6 acres for Rs.60 Lakhs. They splitted that 60 Lakhs into 3, one for my father, one for brother and for my sister, no share is allowed for me. My father is a cancer patient, he undergone two surgeries and various special treatments. I only spent him for all medical expenses even for food. He owed nearly 4 Lakhs of debts I only settled all his debts. Recently my brother and sister ordered me move out of the house and they argued that I’m not a legal heir for my father’s property and I have no rights to live here. Remaining 3 acres is under the will written by my grandfather that these 3 acres of agri land after the enjoyment of my grandmother and my father it finally belongs to my brother and my sister only. It is also an ancestral property for my grandfather. My grandmother and my father requested them to allot 1 acre to me but they refused. Please guide me whether I’m a legal heir or not and I have any rights over my father’s property. Thanking You.