This is also my first time reading NA, so I do not know the answer. But I think the General is a fussy "old" man who rules his children somewhat and when he is out of sorts, he makes everyone tremble.

You know: maybe he's just a jerk?

Your surmise has real merit. I didn't really think of it. I just have gotten the impression that he's cranky and I was content with supposing him to be cranky. But on my first reading of every JA novel, I have been unable to focus too much on these details and simply allow them to unfold. This group read has been great for pointing things out to me as I go along.