Wow! Thank you all for such fast and excellent responses. I guess you've all confirmed my suspicion. In looking again at the mercola.com website, I see that they are actually adding some unique content to each post. I suspect they may have a staff person or copywriter doing this since none of the posts are very long.
I'll re-approach my client and see if I can explain to them a better approach and why it's better in the long run to provide good unique content themselves.
Thanks everyone!