Can vim monitor realtime changes to a file

Don't know about automatically, but you can type:

:e!

to reload the file

You can :set autoread so that vim reads the file when it changes. However (depending on your platform), you have to give it focus.

From the help:

When a file has been detected to have been changed outside of Vim and it has not been changed inside of Vim, automatically read it again. When the file has been deleted this is not done.