JMO if there is a grain of truth in Rachel's accusations somewhere I think it's probably the physical and sexual abuse part because it would go towards explaining the estrangement and the extreme denial of her birth family, and unless I missed it it was something that the family did not deny although they denied the teepee and the bow hunting and the residency history etc. If the older brother is going to face trial there might be some independent evidence that doesn't hang upon Rachel's testimony. And there could easily be very divided loyalties within the family if one sibling accuses another. The brother Ezra said there was no physical abuse but admitted that the family used corporal punishment, and I think corporal punishment crosses the line into child abuse very easily, so that claim could be close to the truth although she might be embellishing the slavery aspect of it for extra effect.
If the brother is a sexual abuser I hope she didn't hurt the chances of getting him behind bars by destroying her credibility making up stories of victimhood.
I agree about where you think that grain of truth might be. Maybe it's because of what I've been reading about the Duggars-all new to me- but I'm reluctant to assume her parents are benevolent just because.
I wonder.....
Is it true her parents sent two of their children to boarding school because they didn't embrace their parents' religion?
Why would her parents allow Rachel to take guardianship of her younger brother? And if they fought it, why would any related courts grant her that guardianship over the objections of his adopted parents? Especially if Rachel was unbalanced in any way at that time?
And again, why is her brother Ezra tearing her down so much in the media? Accusing her of contributing to racism and of playing blackface? Those are very directed comments intended to hurt her where it counts most to her, IMO.
Edited: deleted a last point because it could easily be misunderstood.