My father signed property papers under pressure, how can I challenge it?

I live in Pune and recently found out that my father was pressured by his brother to sign over our ancestral property to him. The property is worth around ₹50 lakhs. This happened last month, and my father is now worried because he realizes the mistake. He didn’t fully understand what he was signing at the time. Is there a way to legally challenge or reverse this transfer? We really need help as this property has been in our family for generations.