What I expected was
His world showing up on the LAN games.

What Happened was
His world never showed up, while other worlds hosted on similar tablets did.

When I tried to join friend with a Windows 10, that had connection to a LAN network that was not connected to the World Wide Web, I did not get a connection. We checkes his settings, but found that the game wouldn't let us change them. He had an Xbox account, I did not. Later we tried it with Internet acces over the LAN network and it worked.

Steps to reproduce:
1. Get a LAN network without Internet connection.
2. Open a world with a Win. 10 Edition with an Xbox account.
3. Try to connect with a tablet.