One understated thing I really loved about "I Can Take It" (I mean, I loved absolutely EVERYTHING about it) is how sweet, compassionate, and competent Casey was. Like, him already having a list of DV orgs/contacts to provide to the brothers. Do you think him and any of the turtles become friends in this universe? Does he get to become their adoptive older brother? Or does their relationship always stay professional? I'm kind of dying for a scene where Grav breaks down to Casey because he knows he's safe or Grid going to Casey for advice or Casey being a surprisingly good helper for Shelle's tinkering or Casey and Blob finding a moment of joy in being silly about comics or something.
Saaame, I love Casey so much. And I didn't say it out loud in the fic but I wonder how many people caught the implication: he has those DV contacts already on hand because he had to use them when he was a kid (hence April freezing up when she realizes.) Then the comments informed me there was some truth to it, that Casey's father was cruel to him in some of the comics, so that backstory worked out well for him. My headcanon is that's partially why the Casey of this universe is a pacifist, as we saw in the '03 episode.
He knows what the turtles are going through and he comes to meet them in the thick of it. This is the coffee order I had when I was going through it (I did consider adding a line that his social worker was the one who introduced him to that mocha as a sweet little boost when he was getting help) so I'm passing it on to you. They might not be as familiar as they are in the normal universe but he definitely starts keeping an eye out for the kids from that day on, e.g. when Grid was overworking himself in this ficlet and Casey was the one to notice and care. I want to write more of his dynamic with them for sure.