Similar story ...
I once flew with a Capt. that included as part of his briefing that, "If ATC asks if we have traffic in sight, we don't have it until
I have the traffic" (I just assumed that there must have been a story behind this statement?).
So ... when he came back from the lav, I advised him that ATC wanted us to start down but that he wasn't available at the moment and that I woud need to check with the Capt. first!*?