After reading what slickschoppers posted about the FOID card and domestic violence, unless she got an Order of Protection, then only these two things apply: 
•The abuser has a criminal conviction of domestic battery or a similar offense in another jurisdiction after January 1, 1998.
•The abuser has a criminal conviction within the past 5 years of battery, assault, violation of Order of Protection, etc., in which a firearm was used or possessed. 430 ILCS 65/8

If you don't have a crimal conviction of domestic battery or similar in another jurisdiction since '98, then it only leaves the last thing and that last one is up to interpretation. Even if your charge was reduced to simple battery, it's still battery. Because it happened in the last 5 years and you did possess a firearm at the time, then #3 is where they denied you.

Sucks and I hope your attorney has some helpful words of advice for you.

"Impossible is a word to be found only in the dictionary of fools." - Napoleon Bonaparte