Legal heirs of Hindu Male

This is a Hindu Male case...My father purchased property and he is no more. We are 2 sons, 1 daughter, and mother ( His wife) , Fathers Mother (Grandmother).Our Grand mother is not well due to bad memory and now my uncle ( Fathers younger brother ) claims that he also one legal heir after his mother ( our grandmother) death. The property is our house which was purchased by our father without any support from uncle and Grandmother. We dont sure about weather any will written by my grandmother favour to uncle...what is the legal implications. Is Uncle claim is valied as per law