A scholar of indigenous Indian Mexican cultures. He authored many books on the Indian writings regarding our Lady of Guadeloupe’s appearance in Mexico. He speaks many languages including the native Mexican Indian language.

Msgr. Guillermo still sings some Syriac church hymns that he learned in 1957 when he last visited Lebanon for a few months. He wanted to stay there longer, but his Mexican Bishop did not allow him for fear of changing his religion from Catholic Mexican to Maronite Lebanese.