(Y) Yes. They have the child.
Article 900 set out the Statutory Share in Inheritance.
Article 900 If there are two or more heirs of the same rank, their shares in inheritance shall be determined by the following items:
(i) if a child and a spouse are heirs, the child’s share in inheritance and the spouse’s share in inheritance shall be one half each;
The spouse is one half and the child is one person, (2 x number of people) per person. In addition, although there was a child, if the child has already passed away, the grandchild will inherit on behalf of the child (suicide inheritance).
As a text, Civil Code 887 (inheritance rights of the child and its transferees) set out the heir.
(1) The child of a decedent shall be an heir.
(2) If a decedent’s child has died before the commencement of inheritance, or has lost the right to inheritance by application of the provisions of Article 891 or disinheritance, the child of the decedent’s child shall be an heir as an heir per stirpes; provided that this shall not apply if the child is not a lineal descendant of the decedent.
(3) The provision of the preceding paragraph shall apply mutatis mutandis to the case where an heir per stirpes has died before the commencement of inheritance, or has lost the right of inheritance as an heir per stirpes by application of the provisions of Article 891, or by disinheritance.
The inheritance of legitimate child and child who is not legitimate in the past has been different, although there was a difference in the past (900 Civil Code).