I think the fluids I gave him this morning helped. He seemed a little more active when it was time to come in. I even saw him eating some kibble, but no wet food.
He's up in the bedroom window now. We'll see how much better he's doing tomorrow. It can take up to twenty-four hours for the full power of the fluids. I do know the tenting test on the back of his neck shows him to be much better hydrated than he was this morning.