Hi, everyone. Thanks for the prayers! DS did get admitted, but was in the pediatric ER area through the night (because there wasn't a regular bed yet) so I was allowed to stay with him. The nurses were very nice, and they even brought in a cot for me to catch a bit of sleep on.
He is still getting IV fluids (but slow ones now) and those and the extra sleep are, I think, helping. The docs seem to have figured out what's going on, but I'm not sure he'd like me being too specific to (to him) strangers, so I'll leave it for the moment that they have a plan in place for him that they think will fix the problem.
He is to stay until tomorrow morning, though, so they can do careful food challenges to make sure he can keep things down.
Only one visitor per patient is allowed right now due to COVID protocols, so DH and I swapped around noon, and I got to come home and take a shower, etc.