His mental health had been declining, hoarding getting progressively worse & he'd visited the doctor etc (wall punching episode). Correct me if I'm wrong someone but I don't think we've been told the date of when this visit occured.
I don't think we can assume she did it to stop him being violently abusive to her, if she hasn't said so herself. She would have said it if that was the case, but she just says she did it in a sarcastic way, and to get him in a good mood.