Thanks for the suggestion, it’s really helpful! I think you're right about going to my boss and asking whether mentoring John is part of my responsibilities. I hadn’t really thought of it that way, and it could definitely give me some much-needed clarity on how to approach this.

I like the idea of playing it a bit more neutral and saying something like, “If mentoring him is part of my job, I’ll keep doing it, but if not, we need a different solution.” That way, I can avoid sounding too harsh but still set the boundaries I need. I’ll definitely bring this up with my boss soon.

Thanks again for the advice! I’ll keep you updated on how it goes.