I really wonder what set Solange off like that. I don't want to jump to any conclusions without knowing the whole story. Unfortunately, we probably won't ever get it.
Julius is like family tho. If he's there, she doesn't need to get involved physically.
I think the idea is that if your sister starts beating the **** out of your husband you'd probably show some sign of urgency or shock and not just chill there. She's unphased in the video we have.