This person was likely selected for duty precisely for (quoting Borat here) having brain size of squirrel.

However, this special grand jury can't charge anyone. So anyone charged would have fun quashing indictments that weren't from this lunatic. I don't know if Georgia requires indictment by grand jury for felony offenses, or some felony offenses, or not. Every state is a bit different. Some states allow charging high level felonies via complaint and others must have a true bill from a grand jury.

If a true bill is returned, it will be from an entirely separate grand jury that likely does not have this idiot as a member. Would be fun to watch a judge roll their eyes at a lawyer even trying to bring this idiot up in the court room as it relates to their clients charges.