You Said ''Your father Purchased the property through Sale Deed'' but you have not mentioned whether your father made the Sale Deed Registered at Sub Registrar Office, If your father got the Sale Deed Registered then you can submit an application and get the property registered on your mother name by submitting the Death Certificate and if your father is a Government employee then Get a Family member Certificate, If your Father is private employee then get Legal Heir Certificate which can be obtained by filing a Case in Court which usually completes within a year maximum