should display the full path of the ftp account's home directory.
Or if you want more info,
grep <username> /etc/passwd
will show you the raw entry from the system's user list for any user, which contains the numerical user ID, default group ID, full name, home directory path, and default shell. (The name of the file is historical; back in the day, it also used to contain the users' encrypted passwords. Modern *NIX systems no longer do this, since the amount of computing power available on modern systems has made brute force password cracking too easy.)
If the world isn't making sense to you, you're either drinking too much or not drinking enough.