Property not equally shared between brothers

My father has sold his share of land to a builder for which he got a lumpsum amount and a 3 BHK flat. The land that he gave was purchased by my grandfather. Moreover, my mother has also sold her share of land to a builder for which she got a lumpsum amount and a 2BHK flat. The land that she gave was purchased by my maternal grandfather. Both my mother and father now gave both the flats and money to my younger brother even without consulting me. I want to go for a legal action. Please suggest.