This summary is not the rule. The rule text controls.
If a parent has been legally declared incompetent by a court (interdicted), or if the court decides the parent isn't mentally able to understand what they're doing, that parent cannot sign papers giving up their child for adoption. The law requires a surrender to be knowing and voluntary, meaning the parent has to truly understand the decision they're making and choose it freely.
If a parent who is mentally incapacitated does end up signing surrender papers, that signature can be canceled later. The surrender would not automatically stand just because it was signed. Another part of the law, Chapter 12, spells out how someone can challenge and undo that kind of surrender.
In short, this rule protects parents who cannot fully understand or make this kind of major decision. It makes sure their rights aren't taken away through a surrender they weren't truly capable of agreeing to.