Nomination of Flat and sale

My father owned a flat in Mumbai, purchased by him through is own funds in June 1960. He expired in 24^th Jan 1976 intestate, the flat being nominated in my Mothers name was transferred in her name by the Society on 6^th Jan 1978. Her name appears on the Share certificate as well. Now can she sell the flat as an absolute owner or partition as per her choice? 

Thanks