tbh that is most likely due to the author not planning in advanced or not being good at writing complex characters
and ig those darker aspects have pretty much been retconned
the best way to read this is to think of it as being entirely separate to it's counterparts and to imagine Grayson as a blank slate in this story
Reading comprehension? You are aware of the omegaverse setting? You understood why he was saying that to Chase? Or not? Because Chase is the one with pheromone management problems, not Grayson.
The author actually thought it was clear for everyone, and was suddenly forced ~8 years after she wrote KMIYC to clarify things....
Should everyone here go over to KMIYC and demand justice for all of Chase's victims? Seriously....one can take it too far.
By the ways, that dominant omega brother loves Grayson and even asks for his advice.

Are we forgetting that grayson said he would fuck his younger brother if needed AND said that an animals hole is the same as a humans' ???? Like I get that he isn't exactly right in the head but that's just pure bullshit dude