A lot depends on the facts of the case, the judge, the prosecutor, your attorney etc. In other words, it can't really be answered. I can say that if the only charge left is a simple battery, then he is facing up to a year in jail. Get an attorney as soon as possible.
Battery is a misdemeanor punishable up to one year in the county jail. Without knowing the facts no one can adequately answer your question at this point.