I know Greyson traumatized chase but did nobody else know or defended him from Greysons ac...

They had one older brother and 2 younger, but each one of them had their own traumas, so I think they don't really care

That family is an extreme alpha/extreme omega family. They have 5 kids who are extreme alphas and one extreme omega. Extreme alphas can have problems with feeling emotions depending on when they present, as it can go so far that they are unable to feel any, Grayson is such a case. I'm not sure how it is with the others, if the are inbetweens, aside from Chase who is a real emo kid. His parents are actually ok, the omega father is really nice, so i don't know what really went wrong there. My guess it that there are probaby problems after they present beeing around extreme omegas (because i got the impression they had less contact with him at some point) or they had seperate the the youngest sibling form the other or it's someting else. And their alpha father was probably too busy with work, and the omega father needs to be near the alpha father because of his health conditions. But that's all just guessing.

Ohh ok thank you both for your replies (▰˘◡˘▰) I’m almost done reading the novel of kiss me liar cause I wasn’t sure if I should just jump straight into kiss me if you can cause I wasn’t sure if they connected

To add, I read some spoillers about the side stories of Lick me up you can, I only read parts of that one and didn't see the side stories. But the alpha father has some problems when if comes to how their chidlren look like (they look like him and with that like the father he hated) and there was an incident where the twins (Grayson and Stacey),where still small kids, tried to foodpoison their omega father, which made the alpha father extremely angry and he got mad.
So i'm no really sure what was going on in their childhood. Both character seems nice in the main story, but there must have been some serious problems when raising their children, how they acted towards them and also the children to each other.
Chase was most likely not the only one with problems there, he was just the most emotional one so it must have hit much harder, and the youngest brother Bliss was most likely the one the parents protected.
To get something out of Grayson is extremely difficult, because he tends to lie and turn everything into a joke. Grayson's way of thinking is sometimes really difficult to understand. So probably the shit he did to Chase was normal to him and the others, but for that one has to actually know how the other children interacted with each other, but in that family it is possible.