and like many have said. If he didn't file an official complaint of the harassment. It most likely wouldn't have been filed. It seems like he brought it up after the breakdown and that whole situation took place.
Like I said earlier. There's a way this probably played out that wouldn't have had the harassment on file.
He got harassed, kept it to himself for a while. And I don't blame him one bit for that. Has a breakdown at work. Gets called into HR about it. He then tells HR about it. Even then it's not an official complaint it's pretty much just a comment in passing. Just based on how corporate culture works. HR probably deems him expendable based on is breakdown. They offer him 20k in severance pay. He takes that as them paying to silence him.
This is how I see the scenario also. If he mentioned the sexual harassment as a part of the scenario around why he had his mental breakdown then there would be no official complaint on file regarding sexual harassment. Depending on how Sony handles documentation they probably have an HR case around his termination but it wouldnt have any conversation logs detailing the reasons around his firing.
Unless he specifically filed a sexual harassment case with HR then there will be no indications at Sony or ND that this occurred. Having spent my career working at large public companies the HR departments are very process oriented and so are all of the modern HR management systems. If you dont follow the process of officially filing a case for each independent thing then details get lost in the process. Its an unfortunate situation.
It is possible that he told HR, HR acknowledged what he said while working on his mental breakdown case but he never specifically filed a sexual assault case. He was fired the next day and HR moved on to the next case. It could have very well gotten lost in the shuffle of a massive HR department. It could also be an evil HR person but in I personally doubt that is the case.