I am over here laughing, and if you listen hard, there is a basso profundo echo in a spring thunderstorm near you! Thank you also for that gorgeous golden tree -- it adds to the vibe of the post!
My guess how he would respond was based on observation of him down to the day of his retirement from opera ... he was as humble as he was gifted, and as full of joy, and was so glad to be doing what he was doing that gratitude seemed to follow naturally. He was still doing masterclasses internationally to around age 75, and his kindness to his students was reported to be as notable there as it was in private settings ... so since we are about that age, and thinking that he at approaching 86 still had things to teach, it seems likely that he would have responded to the invitation warmly, and if gratitude given, likewise returned warmly.