I mean... she accused her father only once he died. Maybe because she was no longer afraid of him?

You know very well that with child sexual abuse there usually is no proof and it comes down to witness testimony. Does that mean unless someone can come forward with video evidence, DNA evidence/a recorded confession from the abuser, that they should just not talk about sexual abuse? Because that would be "accusing someone publicly with no proof"?

I have an aunt who says she was sexually abused by my uncle (her brother) when she was a child - repeatedly, for several years. She has never wavered from that story and everyone in the family knows about it now. Her accused has never denied it, but tries to downplay it. Other family members believe she told the truth but want her to forgive her brother because "it was a long time ago and people change". I do not ever want to associate with my uncle and I hold him in contempt.

Now my aunt could not take this to the police because as you mentioned, there's "no proof" other than her word. But why should she not tell people about it? I argue she should. And I support her and believe her.

Now could I ask her to detail her memories and outline exactly how many abuses she encountered and when and where and what was he wearing etc? No. She has likely forgotten a lot of the details and may have mixed some details up over time. But does that change the fact that she was abused? I don't think so.

I think it's a big stretch to go from "the story Beth is telling has changed over time, there could be a variety of reasons for this" to "I think Beth is lying because she can't tell her story in a completely consistent way and doesn't remember her early childhood with crystal clarity" .