A witness to a document typically is only indicating that they know who signed the document in question. A witness has to be of legal age and sound mind, but does not have to have any relationship to the person actually making out the document.
Don’t draw too many conclusions about a person who only witnesses one of your ancestor’s documents. The witness just might have been another warm body in the office the same time as your ancestor.
© Michael John Neill, “Genealogy Tip of the Day,” http://genealogytipoftheday.blogspot.com, 23 Oct 2012..