Whose property you are referring to?
If it is the property of Parent/s, they are free to bequeth the property as they wish.
If it is the property of Son, cash in bank, insurance etc shall be dealt with as per the nomination of the deceased. As rightly pointed above, it's the responsibility of such Nominee to distribute shares to other legal heirs.
In case of immovable property of deceased Son, if there is a Will, property devolves as per such Will. If there is no Will, all legal heirs shall get respective shares as per the religion of the deceased Son.