When you hit a brick wall, it might be worthwhile to look at all the names in the family. Can you account for all the names of the children? Could one of them be named after a grandparent or former spouse?
Last names can provide clues about a place of origin. Different suffixes in surnames point to different regions.
A matching name does not amount to prove, but it is evidence we can use to guide our research and can help to build our case.
See this article about Naming patterns for more information.