After my wife and I disagreed we went back to the shop to ask a DM their perspective (we needed a referee lol), and the short of it from her was, to paraphrase, "Depends on situation, and reading the room. If you think you can constructively share your concern in a helpful way that you believe will be received as intended, then sure it is worth communicating. Unfortunately far too many divers are submerged in their own egos, and can be difficult to reach even with the best intentions. I would at the least support a firm re-signal of "pair up", maybe with some angry eyebrows to reinforce the point. Once on the boat though every situation is different. If you think your buddy is a danger to themselves or others, definitely pass on your observations to the staff, and let them decide how to address from there. We don't want anyone dying. Too much paperwork (tongue in cheek)."
I can also note the reality that I am probably less likely to address such concerns with a female than a male. I am conscious of the perception of mansplaining, and I don't want any part of that convo. My wife says if it was a dude I would have been blunt and said, "WTF, Richard?" I disagree, I would have likely said little to nothing, but she is not incorrect that it may be a trickier business than usual for an older guy to start dishing out post-dive criticism to a younger woman. The line between helpful and demoralizing/irritating is too narrow for me to walk. I recognize a single female on a dive boat is on one hand just another diver, but on the other hand there are considerations of culture upon which I wish to tread lightly.