Re: Jewish gauchos Argentina #latinamerica
Last year I looked for info about my family and discovered that the Jewish Colonization Asociation (JCA) had a very strong filing system of almost everythig: letters, telegraphs, draft notes, lists of emigrants from East Europe to South and North America, ships, detailed list of colonies and colonists, etc. It runs from 1870's till 1950's. If your mother's uncle contracted with the JCA by any kind of way, it is probably to find some hint about him. On the other side, if he did it "his way" and decided not to contact JCA, may be that there are no signs about him.
A copy of the archive is at The Central Archives for the History of the Jewish People in Jerusalem. Just very little of all the material has been scanned and a more little part is online.
My experiance with CEMLA is not good. The index system is very strict and every new search asks to insert a captcha code. Most burial registers from AMIA are indexed in JG.
If you have any name you can contact me and I'd try to help you based in my experiance. Most probably that it will demand a personal search in the archives, but they are closed now because the COVID.