The reason you speak up even if it's too late- because silence is a terrible burden. It's like living in an alternate reality.
In one world, her mum and stepdad were respectable people with a good family network, career and friendships. She addressed that with the step father- legal recognition that she had suffered, that he had been abusive.
She needed to address it with her mother too- she existed, she was abused and traumatised and suffered and her mother... only cared that it disrupted her own life and image.
It takes massive courage to be the lone voice speaking against the rest of the world and particularly against your parents. So she didn't complete the task until her mum was dead.
That's ok. It doesn't negate the power of forcing the alternate reality back into line with the truth.
When Ulrika Johnson published a memoir referring to her rape, she was massively criticised. But if she left it out it wouldn't have been her story. It would have been a lie.
I carry a similar story and the prevailing assumption that 'it happens to someone else' is really disconcerting. People assume it didn't happen to their friends, colleagues, family. But of course it did.