My best advice, to make the will a self-proving will, is to have two witnesses, plus a notary public. Everybody should be present at the same time. You mom should sign in the presence of the two witnesses and the notary public, and each of the witnesses should do the same. Then have it notarized. This will give your mother the best protection. (It is also best to make sure that neither the witnesses nor the notary are beneficiaries under the will).
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