So, what does the guy do? What are his actions that are unsafe? As stated before, you are the captain... you were hired to be the Captain/Chief pilot and are the one the owner has entrusted his and his families safety with.
Maybe you can come up with some sort of ops manual and get the boss to sign off on it. Make everything in it about safety, then when your co-pilot does something unsafe just pull out the manual. Also, if its a single pilot plane and you can operate it that way, then do so. Every leg is the captains leg. Remember... the F.O. flys at the captains convenience.
Bottom line..... you're in charge. Dont let the guy push you around and cause you to get fired..... then again, maybe thats what he is trying to do.
