Isn’t this the guy who traumatised his own brother accusing him of raping a dog for his ...

Please don't spread misinfo. It wasn't for his own amusement. It also wasn't mentioned like that in kiss me if you can, like at all. I've read the novel.
If you want to know the details you cannot see in kmiyc, you can read this. This is all about Grayson as a character. If you don't, you can also scroll away, it's fine.

I wldnt call it amusement, he.was just trying to help chase in his own deranged way to help him deal with his rut. Lets just say dude thinks abit differently from normal ppl