Letters from Jaime Holcome

I just ran across some documents attributed to letters from the late Jaime Holcombe. One of the documents has some very valuable information regarding one of my lineages (a very important one because I have five lines going back to these people). I know that Jaime Holcombe passed away some years back but I am wondering if anyone is familiar with his work, would know where to get authoratative copies of it (perhaps with sources) as well as if there is an official repositor of his research that I could contact?

The issue I am looking at is the connection between the descendants of Francisco Escobedo, founder of Monte Escobedo and a certain Isabel de Rodas or Isabel de Covarrubias who married a Captain Jacinto Talamantes circa 1630 probably in Zacatecas.