I think the person gave you accurate information. In order for you to find someone, you have to look at their child's death record. There are also possibly birth or even marriage records that can contain names along with where they were from. If you want information prior to 1910 you need look at the records that are available on the familysearch website. The website has records for Puerto Rico going back to 1643 and a multitude of Spain records as well.
https://www.familysearch.org/search/collection/list#page=1&a...You can actually go through the digitized images.