THANK YOU !!!
That's what I have been saying since the first chapter :
WHY ARE WE ALL IGNORING THE GRANDPEDO WHO STARTED ALL THIS !?
Well, I can tell you one thing.
The MC sure as hell didn't report it to the police, or his dad who is a cop.
As for her, that's a parental figure, who knows how many years she had to deal with this. She even straight up said that he was her escape from this when he said he would marry her... When they were kids.
Meaning that she possibly was being raped when she was in the one digit year of age. And the miraculous moment when the grampa got caught, where the MC could have made a decision that would have saved her from who knows how long she was suffering. He ditched her and evaporated all hope she had kindled in her ever since they were kids.
This manga is doing a good job making the MC less and less likable and salvageable and more and more deserving of everything coming his way.
Was he raped? Sure. But we've also been given hints that he deep down might have enjoyed it in his own sick ways, after all he's a teenager running high on hormones who was pleasuring himself at the misfortune of others.
But of the three victims here. He's the one with the least sympathy going his way, because he so heavily offsets it with his horrible behavior and thoughts. Miya is just an unfortunate innocent bystander who got involved with a scumbag MC and a broken menhera girl. And of course Ayana is the biggest victim here. If anything, as we continue forward in the manga, we're just discovering more and more how much screwed up her life is, and how little the MC has done to do anything to help and in fact has done a lot to actively not help.