Firstly, some very good posts here. But, as ever, the most important thing is "fly the plane". But when that has been accomplished you have to remember that unless you do something, the onerous little git will be back and on at you again. And you are NOT the only one affected.
As ever, many ways to skin the cat. Some suggestions:
1. Make sure that they are correct in their calls and RELLY have a go at them if they are not - going the whole nine yards.
2. Point out that you are the one in charge and they are not - if they care to dispute this, they can get off.
3. If their manner ever gets to the point of getting close to jepodising the safety of the aircraft - stop at the next scheduled stop, file an ASR/MOR and refuse to operate with them.
4. If you are a bit of a miserable old git like me, take them behind the bike sheds and educate them.
5. Make sure matey boy gets no fun when he flys. No raw data, A/P - A/T - FMS (as little AFCAS as possible), No hand flying, No interesting approaches, no non-std stuff whatsoever. Also, no chit-chat.
6. Never, ever let the git encroach on your territory. Even if just to be bloody minded and always put them down in front of others if ever they do.
Either way, they have to conform to the standards - this is not the industry where renegades should be allowed to flourish.