In re Gordon's Estate, 40 Nev. 300, 161 P. 717 (1916):
That a signature to a last will and testament is not rendered invalid by reason of another having aided the hand of the testator is supported by a line of eminent authorities. ( In Re Miller's Estate, 37 Mont. 545, 97 P. 935; Vines v. Clingfost, 21 Ark. 309; Craighead v. Martin, 25 Minn. 41; Fritz v. Turner, 46 N.J. Eq. 515, 22 A. 125; Sheehan v. Kearney, 82 Miss. 688, 21 So. 41, 35 L. R. A. 102; Jarman on Wills, pp. 106-111.)
In order for this rule to apply, it must appear that the testator, at the time of requesting or receiving the aid in the signing of the instrument, had the present volition to affix the signature, and was aware and fully cognizant of the details of the instrument of will or testament to which he, by the aid of the other, was affixing his signature. The fact that the signature of the testator was made in the manner indicated by the record here would not of itself invalidate that signature. Hence we must decide--and we do this in the light of a harmonious line of authorities--that if the testator in this instance possessed testamentary capacity, was acting under no undue influence, realized the full force and effect of each and every one of the provisions of the will that he was signing, then the signature, in the manner in which it was made, as described by the trial judge, was a valid signature.