Living in Parental property for 14 years

Hello I have 2 older brothers and my father brought 2 houses in name of each of my bothers. The first house that my father gave to my elder brother i gave half amount in that house but i dont have written agreement. And in the second house i gave 1/3rd amount and no written agreement as it all was done before my parents were alive. They have papers in their names. He did not buy me a house. Before dying he said the house in his(my father's name) will be mine but he did not wrote a will. After his death i was living in his(my father's) house since 15 years. All the expenses of this house are paid by me only. I was ready to pay my elder brothers the difference of money of this house and the house my father gave to them in their names but thet do not agree and want the equal share. Now this house is very old(around 60 years) and its condition is worsening day by day. So i decided to build it again and i started to build it ,now they came and said we want share in this house and if you dont give share we will do court case. 1.) Now what should i do ? Should i proceed to build it.? 2.) Can they take any legal action and the court will put a stay and i would not be able to build this? 3.) Do i have to give them the share they are asking after taking everything just because i did not maintain any written agreement and this house is in my father's name ? And if yes upto what extent i need to pay them as i came here 15 years ago Thankyou in advance.