I would change a couple of things.
"He insulted his sister in front of everyone and made derogatory remarks about her. His sister felt ashamed in front of everyone."
Student or Learner
Please check "He insulted his sister in front of everyone, passed derogatory remarks for(or regarding)her. His sister felt ashamed in front of everyone"
Mike's suggestions are all good. Use about, not regarding or for. (Regarding sounds stiff. In the sense of about, it's mostly used for business letters. For makes no sense at all.)
You might also change ashamed to embarrassed or humiliated. Look them up to decide which is the best fit.
I am not a teacher.
I thought the same thing about embarrassed or humiliated for her.
As for him, he's the one who should be ashamed.