In DW's Site Manager, export your site definition including the FTP information, and send it to them. They would then IMPORT using Site Manager.
Be VERY careful! This is a great way to get into version control hell. You might consider enabling CheckIn/CheckOut for the site to protect yourselves - but everyone MUST play by the rules when you do. Each of you must have your own local site to do this. What you are sharing is the Remote site. Your local site becomes your scratchpad for edits of the remote files....
Can you do what without a server? Have multiple people work on the same site on different computers? How much risk can you tolerate? Yes - you can do this without a server by sharing your local site. The risk of file version problems is immense with such a system.
DW supports multiple people working on the same site with a fairly simple system called CheckIn/CheckOut, or with very sophisticated systems like Subversion. If you are serious about your work, you would use one of those systems. Can you use one of them without a server? No.
What is your problem with setting up the server?
Apart from what has already been said, have you thought of creating your site in Wordpress? In WP you have multi-user, multi-developer pretty easily.
You could try creating a test site free of charge on WordPress.com and I believe this is another option worth exploring. Corel have their blog on WP free of charge for many years now.
To register a new WP site:
Corels blog on WP:
On Wordpress you can have static websites like you have in DW so don't ignore this option.