I have been in touch with your brother and his wife.THe marriage investigation of Desiderio de la Cerda and Luisa Rodriguez Saenz stated that Luisa's grandfather Diego Saenz Trevino was a first cousin of Desiderio's father Juan Trevino.Diego was a grandson of Leonor Ayala and her husband Joseph Trevino.Diego's mother was Ana Trevino as stated in Saltillo Tomo III by Guerillmo Garmendia Leal. Leonor and Jose Trevino had a son Juan but he is supposed to have been a bachelor. I have been looking at the Protocolos for Monterrey and looking for the testamentes of Leonor and Joseph Trevino's sons.THe son Jose (who went by Jose Ayala in Leal's genealogy) did have a son Juan who died before Jose Ayala died in 1692.According to the marriage investigation which was dated Jan 1697, Juan Trevino, Desiderio's father was desceased by this time.This is a possibility.If you look at some of the other indexes for the protocolos for Monterrey you see that the land that Desiderio sol was bound on one side by the land by DIego de la Cerda ( DIego was the son of Fernando de la Cerda, the man who helped to raise Desiderio ) and on another side by land owned by Jose Trevino.I don't know if this Jose Trevino is Jose Tevino AYala or a cousin of Jose Trevino Ayala who had the same name. COnfusing isn't it. It might help to get full copies of those documents in the protocolos of Monterrey. The index is only and extract.There might be information in the portion of these documents that was not shown.