That's weird. My game is playing in survival mode.
The server gives me the ability to create up to 3 worlds, but only one can be active. All my settings point to a survival world, so not sure on where it is an issue. Are you sure you're connecting to our server? I've set up a new Survival world, see if this changes anything.
@crispymorgan your son might be a little confused if the world seems to have been reset, just so he knows while we try figure this out. Can you also ask him if when he is playing, he is playing in Survival mode?
EDIT: New world seemed corrected, so we will continue on the new world. I've also set the game to keep inventory upon death, hopefully everyone is okay with this.