Sorry but I'm having a hard time getting a straight answer on this. Is it possible?

Poster in my other thread about the 4G LTE router says you don't even need the router but in same breath says tablet sends data via wifi, but isn't connected to wifi, only 4G. I can't be connected to both 4G and wifi at same time. DId he mean to say Bluetooth? Does the Apple TV need to be newer Because it doesn't work that way at my house but my Apple TV is older.