Article 177 — — (2) Exception.

1) Where the person to whom the paternity of the child is attributed by law dies or becomes incapacitated within the time fixed by law for instituting the action to disown, one of his descendants, in his stead, may institute an action to disown. 2) In default of descendants, the right to disown may be exercised by his father, or mother, or in their default, by one of his ascendants. 3) In default of ascendants, it may be exercised by one of his brothers or sisters, to the exclusion of any other heir or representative.