You know, I'm willing to hold forth at great length about the deficiencies of my OW class. But I will say one thing for it: There was NO doubt in my mind, when I finished it, that someone with my training was not supposed to go inside of ANYTHING. It was made quite clear, and repeatedly so. I don't think we need to add anything to the class to accomplish that.
I've followed this thread from the beginning, and I have to say that it disturbs me a great deal that someone who has taken a cavern class would seem to be so unperturbed about diving with someone who is described the way the OP has described her buddy: "Risk taking", "self destructive behavior", "inattention", "lack of communication". I haven't taken cavern yet, but I took a wreck workshop where we had to do no-viz exits on a line, and I came away from that experience with a very profound respect for the dangers of getting yourself into a position where you have to follow a line out when you're blind. I cannot imagine agreeing to enter any kind of overhead environment with someone whose skills, judgment and responsibility I did not absolutely trust. Nor can I imagine agreeing to any dive without having done the research on the topography and conditions of the site, especially if it's an overhead.
Either the OP's cavern class didn't convey the seriousness of overhead diving (which, as I suspect I know who the instructor was, I doubt), or the OP didn't absorb it, or she's letting the desire to dive at all costs make her turn a blind eye to the inadvisability of diving with this companion. Or she's got a far higher risk tolerance than I do.