27 Years Old Unregistered Declared Will.

My Grandfather executed a Unregistered Will in 1994 in favour of my father and he died in 1995, In 2013 my Uncle filed a Partion Suit but my father replied he has a Will in his favour, On the basis of my Grandfather Will my father executed a Registered Will in 2015 in favour of me and my brother, My father also filed a Probate Suit in 2018 and submitted that Unregistered Will with Probate Suit with the affidavit of one Attesting Witness. Nobody challanged the Will till date. Now my father died on 04-12-2022. Now can my Uncle challenge my Grandfather Will after 27 Years of its execution. Please advice what should we do ?