There's no need to resent them. And bugger the forgiveness and understanding. What's more to understand than her brother is a thieving piece of shit, her mum is a narcissist and her dad has no spine.

If she shuts those arseholes out of her life then she won't be thinking about them.

It should be said repeatedly forgiving toxic people is poisonous to oneself.

Fuck that. You have no obligation to other people.

"Forgiveness" is the skeleton key abusers use to keep getting back in.