Is AUTHOR wrong in the post ? POST : Sorry for formatting I’m on mobile

So I want to preface this by saying we’re in high school in our sophomore year. The group I hang out with aren’t necessarily my friends except for  3 of them (10 in the group). They actually have a whole separate group chat without me but my 3 friends still dm me and a group chat were in instead. The guys are very big dicks to everyone and I don’t associate with them at all. But in the past they weren’t dicks and we were my actual friends. I’ll refer to my friends as friends but will refer to the others as “friends”

So they’re all below average when it comes to grades (D’s and C’s) whereas I’m a B’s and low A type of student. One of the “friends”  is around 0.50% off from failing an English class which I also have (the rest have another teacher). I used to help most of them out when we were actually friends but now I don’t considering how stuff they do to me and other people. (All verbal rarely physical) I never say “no I won’t help you”
Or anything like that instead I’ll usually say something like “no I don’t know how to do that” 

So reddit am I the asshole for not helping him/them?