Article 839
ART. 839. The will shall be disallowed in any of the following cases: (1) If the formalities required by law have not been complied with; (2) If the testator was insane, or otherwise mentally incapable of making a will, at the time of its execution; (3) If it was executed through force or under duress, or the influence of fear, or threats; (4) If it was procured by undue and improper pressure and influence, on the part of the beneficiary or of some other person; (5) If the signature of the testator was procured by fraud; (6) If the testator acted by mistake or did not intend that the instrument he signed should be his will at the time of affixing his signature thereto. (n) SECTION 2.—Institution of Heir