My mother in law actually throws fits and cusses like a mexican street walker. Once she hit my wife when I was out of town.
I totally believe you. My mother was very abusive to us as kids, and to her own mother. My sis was a mess emotionally and my mom ended up keeping my niece for about 3 years. She abused her during that time bad enough that my niece started "cutting" herself at the KH. My mother drank 16 oz cans of Schiltz Malt Liquor Bull. Believe it. She cursed at her mother and us.
But at the KH butter wouldn't melt in her mouth. It is mind-boggling and soooooo frustrating when no one will believe you, and you feel as if there's nothing you can do. You feel like you are in some kind of Twilight Zone repeat.