It isn't really clear. I believe you have to reference his other post. I think he wants to actually remove the patients due to space and performance. Everyone has stated that would be a) very difficult and would have to be done at the database level and b) it likely wouldn't save much space or make the database more efficient.
I wouldn't say it would be THAT difficult.

The problem would be if the practice ever had to reinstall AC - you have that second "archive" database that may no longer be recognized by that pesky process AC has going on now for setting up a new server.
JamesNT