La. Civ. Code art. 257
The right of appointing a tutor, whether a relation or a stranger, belongs exclusively to the father or mother dying last.
The right of appointing a tutor, whether a relation or a stranger, also belongs to a parent who has been named the curator for the other living spouse, when that other living spouse has been interdicted, subject only to the right of the interdicted parent to claim the tutorship should his incapacity be removed by a judgment of a court of competent jurisdiction.
This is called tutorship by will, because generally it is given by testament; but it may likewise be given by any declaration of the surviving father or mother, or the parent who is the curator of the other spouse, executed before a notary and two witnesses.
La. C.C. § 257