My fience is in jail right now and he violated his probation so he has court tomorrow for it and its 6 months over his head . How much of the 6 months could he get ?

He might have to do all of his original sentence and not just what his probation was. Only the Judge can decide his sentence.

Not sure what you mean by "over his head" what was the original probation time, that is how long he could go back for if they wanted to.

You also did not say why he was violated, a failed drug test or robbing a drug store, all makes a difference