I have a user who is a subscriber, and I would like to add him as a host admin, but I can't seem to find where to delete him from the user list on the site.  I can see him if I go to "site", "Users", but no delete user button.  If I try to add him as a superuser, it says the user exists already (which he does as a user of the site), but I can't seem to find where to delete him as a user so I can add him as a superuser.

I think you are right.  I may have put him as the admin of the portal when I created it, since It's been a while since i created it.