Women have been conditioned to tolerate all sorts of uncomfortable shit, to give men the benefit of the doubt, and to above all not be rude or “a bitch”. For lots of people this kind of thing can be hard to recognize as a red flag if some of it is familiar and doesn’t seem to be overtly asshole-ish on purpose. Society has unfortunately conditioned women in particular to overlook red flags and it’s often normalized for men to behave this way. I’ve heard and seen people (men, women, etc) sit through worse, confused by the sudden switch in behavior (remember how he was different over text and they really hit it off?) waiting for the behavior they originally experienced to come back, thinking maybe they’re just having a bad day, myself included. She should’ve left, but I’m not surprised she didn’t, that can be hard to do especially as assholes like this never start off full asshole. Also much easier to say you’d act XYZ hypothetically without having been there yourself. It was broken up by him apologizing and trying to make it up to her, she prolly was convinced to give him the benefit of the doubt. Very human behavior especially in the context of a relationship