Property dispute among children

My father is an ex-serviceman(army) who owned a house in Kerala, earned on his own. We are three children. He has gifted the full house to my younger brother about 20 yrs back without informing us or giving our share. I was sent out of the house 2 yrs of my marriage due to family fights. My brother was staying with them. I came to know about this 2 moths back. Can I or my son (his grandson) claim our share of the said property. We did not know about this gifting nor we signed any documents.