My Fathers brother trying to file a property share suite where he is not entitled for.

Hi All, Good Evening! My Name is Praveen, I have a question. Brief Background: My father have 8 siblings, all the property is being divided by my grandfather 27 years back. The house where we live at present was shared between 2 (my father and his younger brother), my father opted the property and paid him his share amount (with which he constructed a house and living there).. all these years the property is on my grandfather's name, there are no documents related to this transaction. 6 months before my father got this property registered on his name and 3 months later he transferred properties to me. Now we are planning to construct a new house in this site by demolishing old house (100 yrs old). I came to know my father younger brother is in plan to file a law suite for this property share. we are concerned about this, since we are planing to construct a new house(by demolishing old house) in the land where my family living for past 35 years. Please advice what would be the precautionary actions which I need to take in order to construct a house. What if I receive a case document after I begin with construction, which I don't want to be in that situation. please advise how to react and what all measures to be taken in order to handle this situation. Thanks in advance! Praveen