Princess, i don't really know about the regulations in your airline , probably few hints might help you stop this " PURSER" from what he's trying.
can you submit a confidential report ? do you a have a direct manager with whom you can disclose the issue ?
at the end of the day , the PIC of the flight should be responsible of his/her crew, and should either take action or logged in his voyage report for line manager decison, don't look small because you are junior,especially when your purser doesn't know how to lead by exemple, all the best.