So you are suggesting it's possible he was physically abusive to SW and the girls and that's why he never lost his temper in public, or never losing his temper in public might hint at physical abuse no one else saw?
Because many people never lose their temper in public, or get angry in front of other people. I don't believe it's a red flag that hints at them being physically abusive behind closed doors. I have also know abusers who often lost their temper in public, yelling at waiters or people standing in line, customer service reps, etc., or getting angry and yelling at their spouse in a public setting. That's more of a red flag, IMO.
It's unreasonable, IMO, to say people not losing their temper is some kind of red flag. It's acting like a reasonable, respectable adult.