How old was Jeff brown the author before he died?

Please provide more information about the author you are referring to. There are many authors named Jeff Brown.

For example, are you referring to:

* Jeff Brown, the author of the children's book series "Flat Stanley"?

* Jeff Brown, the author of the book "The Darwin Economy: Liberty, Competition, and the Common Good"?

* Jeff Brown, the founder of the website "The Brownstone Institute"?

Once you specify which Jeff Brown you are asking about, I can help you find the information about his age at death.