I would not let this affect my views of Rev. Graham.
Tragically, some of these abuse victims are in such an extreme trauma-induced mental state, possibly exacerbated by forced intake of drugs, that their grasp of reality is questionable.
What I mean is: They MIGHT have been raped by a famous person; or, more likely, it could have been some other sicko wearing a mask.
Convincing them their tormentor was a famous person is another way of devaluing their testimony.
I just know that because of the personal connections with those who have known Graham face to face, I'll need a lot more than internet claims to believe such. And, imho, Franklin is even more foundationally authentic in his lived-out Christianity than his Dad--maybe not by a big margin since I see them both as high on that scale.
Nevertheless, reality is so incredibly complex; human nature is sooooooo prone to sin; pride and power are so corrupting, lots of inconceivable things are actually more than a little conceivable. I don't see conceivable as = to truth or reality, however.