Is it possible to archive / close a Workspace?

[Jennifer]

I have information saved on boards which I am no longer using right now. I may need it in the future so I don't want to delete them, but I'd like to archive them within the Workspace.

The boards contain medical records for my dad, from different locations or time periods. I have already archived / closed them...

The Workspace contains all of them and is his name... which is why I really don't want to just delete the Workspace. 

[Daydreamer Mike]

So long as you were a creator/member of the boards or they were workspace boards and you were the member of the workspace, the boards wont be deleted when you delete the workspace.  The boards will be closed if opened and they will become your "personal" boards, you can find them at https://trello.com/my/boards 

For more information see this:

https://support.atlassian.com/trello/docs/deleting-a-workspace/