Sounds like you should be using Document Sets with default metadata configured.
You can, however, achieve this using the Column Default Value Settings in a Folder as well.
Here's a nice blog with a comparison: Document Sets vs. Folders in SharePoint 2010
"Document Set" is actually a content type that inherits from the "Folder" content type, but it allows you to configure default metadata on the contents as well as a welcome page (rather than a default view). The biggest difference for you between using the Column Default Value Settings of a Folder and a Shared Column with default metadata in a Document Set is that if you change the default value of the Shared Column, it pushes the change to every document in that Document Set.
A use case that I can see for this would be a name change due to marriage or divorce. If you wanted to update all of the documents to reflect the name change, the Document Set would be your answer. But if you did want to retain the name on the document at the time the metadata was set (on upload), you should use Folders.
The default value can be configured manually OOTB when you create each Folder or Document Set, but to set the default value automatically upon creation you would use a content type event receiver, which is custom code (see Developing an Event Receiver for a Content Type).
Also, here's some other useful links:
Document Sets: Making Your Metadata Shine
Working with SharePoint Document Sets