Use WinSCP
with Directory Synchronization option. There is synchronize
script which will make it automatic. Check the Automate file transfers (or synchronization) to FTP server or SFTP server guide.
Then Notepad++ should notify about changes made in file automaticly. The option you're probably looking is disabling the confirmation which can be found in Settings -> Preferences -> MISC -> Update silently
.
There is also DocMonitor plugin for Notepad++.
Document updater updates your opened documents in Notepad++ every 3 seconds
You can find it in Plugins -> Plugin Manager -> Show Plugin Manager
as Document Monitor
.