He is mentioned in this capacity in the design for decorations commissioned by the Portuguese Franciscan, Josè Maria de Fonseca y Evora, for the festivities surrounding the canonisation of the Franciscan saints Jacopo della Marca and Francesco Solano in 1727 and Margherita da Cortona and Giovanni da Prado in 1728.
These decorations were installed on the façade and in the interior of S. Maria in Aracœli (the Franciscan church on the Capitoline Hill in Rome) and are known through engravings.
Alessandra Marino believes that the design for the highly unusual façade decoration should be attributed to Dos Santos, rather than Giuseppe Sardi.
Dos Santos’ most important commission was that of the church, convent and hospice of the Trinitari Calzati, which extended from the via del Corso down the via Condotti.
Dos Santos worked as the architect for the fathers of the church of S. Antonio dei Portoghesi from 1733 until 1750, mostly on ephemeral architecture and the provision of perizie and stime.