Connect filezilla to root login

SysAdmin who was working in our company setup Ubuntu to this way: I am login as admin and run su-, put password for root and I can run commands. Root user doesn’t have home directory. Our developers needs to move inside ubuntu files using filezilla or winscp. They can’t connect such application to ubuntu using root password. I can change root password. when I tried to create home directory I receive message “user root exist’. Maybe you can suggest how I can get from this loop? Thanks in advance.