Since I haven’t been able to make any breakthroughs researching Froilan/Froylan de la Garza (father of Candelario de la Garza) directly, I went back to look at his first child, Jose Ysidro Garza Martinez’s baptism record.
It names Antonio Escamilla and Maria Josefa de la Garza as the padrinos (godparents), so I researched Maria Josefa.
Maria Josefa de la Garza and Jose Antonio Escamilla were married in Santiago Apostol, Santiago, Nuevo Leon, Mexico in April of 1826. The record says her parents were Anastacio de la Garza and Maria Ignacia Valdez.
Looking at baptism records naming this couple as the parents, I found one for a Jose Froilan Garza Valdes in Santiago Apostol, Santiago, Nuevo Leon, Mexico on 10 October 1803. It says he was “Español”.
Compared to Maria Josefa de la Garza’s baptism in 1810, Santiago Apostol, Santiago, Nuevo Leon, Mexico. It is also noted on her baptism record that she was “Española”.
I think Maria Josefa de la Garza and Froilan de la Garza were siblings, and that their parents were Anastacio de la Garza and Maria Ignacia Valdez.
Full disclosure: A cousin has another suspected Froilan Garza (https://www.familysearch.org/tree/person/details/M2N5-5JK) attached to our Family Search Tree, but that Froilan’s wife is listed as Maria Antonia Salazar and he was from Vallecillo, Nuevo Leon instead of Santiago. This all is important to note as we know our Candelario‘s mother was Maria Rita Martinez, not Maria Antonia Salazar, and that Candelario was born and baptized in Santiago as this family I’ve shared here.