Imagine your brother and your sister both stagger back from a drunken orgy. The brother says that a woman threatened him and drugged him and forced him to get an erection and copulate with her. The woman had a gun and a knife and a daterape drug and was blackmailing him, and she was stronger and taller than he was. He feels humiliated.
Your sister says she was raped.
I suppose you could make the argument that the crimes were the same, if you did not care that the argument was mere sophistry. In reality, you need to go get a shotgun and kill the boy who raped your sister, or, if you live in a state civilized enough to have a death penalty, turn him over to the law for a quick trial and a slow hanging. Your brother, maybe you need to buy him a drink and lend him a sympathetic ear.