I've experienced a similar situation. Here's my advice and how I handled it:
Take the job as described. Take the "vibe crasher" guy under your wing; be nice to him, tell him you'll show him the ropes, etc.
At the shoot, send him on an "important" errand. When he gets back, be sure to really tell him what a great job he did, how he really saved the day. After an hour send him on another "important" errand, etc. You get the picture.
You crash his vibe, he doesn't crash yours.
Good luck.