1) Have your friend go to his registrar and set the Name Servers (DNS) for his domain to ns1.dreamhost.com, ns2..., ns3...
2) Create a Fully Hosted Domain for that domain and upload his files. As soon as DNS propagates, his site here will go live.
If he will be administering his domain, make sure you create a New User when you create his domain here. That will give him his own FTP access to his domain. Heck, create a New User, regardless, even if you'll be uploading the files. That way if he wants access, you can give him the FTP username and password.