I've read enough manhua to know that there's this unspoken rule of "once an asshole, always an asshole." That's the usual pattern anyway.
Idk if it'll actually hold true for this story. After all, Class Prez kinda has this neutral vibe to him. While I don't exactly like the dude, as long as you don't get in his way, he'll more or less respect your space and leave you alone. That's certainly different from other manhua I've seen. Normally, characters in a position similar to the the Prez tend to do everything in their power to fuck with the MC.
This former bully could have turned himself around, but there's always the small possibility that his "nice guy" act isn't genuine. I'll give him the benefit of the doubt for now, but I'll just continue watching to see where this goes.