So maybe he is a little paranoid, but no matter what the Detective says it's warranted. His mother, the Goddess, is finally free after centuries of imprisonment, of course he is paranoid.
But even he starts to calm down after days of silence.
Of course that's the moment Mother walks into his penthouse, limping and covered in blood. Of course.
In the end, he puts her in Maze's clothes and resolves to check out the murder scene she so readily left behind. Good Dad, he doesn't want to clean up after his mother; and no, he doesn't believe her when she says she didn't kill anyone. He is not an idiot.
The Detective gets the case, and he tries to find some evidence pointing at his Mom, but it doesn't happen. Instead it looks like she actually said the truth, and she managed to find a pretty dead body on her own.
It doesn't change the fact that he needs to send her back to hell, if he wants the Detective to be safe, but he can't.
He can't.
No matter how much she hurt him, she is still his mother, and he wants more than anything to fix what's broken between them.
So instead of taking her down to her fiery prison he punishes her with humanity. She always hated them, so what's crueler than making her live their life.
It's a win-win.