Limitation period to challenge will of property transfer & ownership

My grandfather expired in 1992 post which my grandmother got his house transferred in her name the same year. In 1999 she made a will wherein she mentioned the share given to my uncle and aunt in form of cash, jewellery, etc. and that the ownership of this house should be transferred in favour of my father. Now in 2017, my father got this property transferred in his name and sold it too. My uncle has now raised a dispute challenging not just the will but also the transfer of property in my grandmother’s name way back in 1992. He’s claiming all of it too be forged which is not the case. I would however want to understand what is the limitation period for challenging the transfer of property in my grandmother’s name and thereby also for that of challenging the will and the ownership in favour of my father?