J.S.
Unless it was acid there is nothing inherently harmful about being wet. My kids used to sweat a lot and be wet almost every nap, yes we ran the AC, they were just little space heaters.
Anyway to me they did the right thing, I would rather let my kids sleep than change damp clothes. After all if they actually were uncomfortable they would wake up and cry as most babies do when they need something.
So considering he was comfortable enough to sleep, where it the neglect? Is there something else going on here?