I pray that he gets better soon, as well. But I'm not terribly worried about him at this point. It doesn't look like any infection has set in. My main concern with the Meloxicam is to help him with discomfort and inflammation. We ended up giving him half the vet's recommended dose.
He ate a lot of broccoli today, which is a relief. Unlike some of our other ducks, who will eat anything and everything, Bob has always been rather picky. I had been trying to tempt his appetite with all sorts of different things, most of which he rejected. I don't really blame him for not wanting to eat when he doesn't feel well.
His lethargy is not severe, and he doesn't seem to be weak. He is still active and feisty, and will swim, fly, and move about freely. His posture when he is resting looks rather uncomfortable, though.
His prolapse looks a lot like this one:
https://www.backyardchickens.com/threads/prolapsed-duck-phallus-need-help.1605272/page-5
You also advised this duck's owner on how to deal with it, and it turned out well. I'm glad you never had to medicate any of your ducks!