Player stuck falling under minecraft world

5 year old was playing Minecraft and came to me saying he mined strait down and fell off the Minecraft world and the fly feature wouldn't let him fly back to the hole. It looks like the character is in constant free fall. When you fisrt start the game you can see something like a hole above you but it recedes away. The time of day changes like normal from day to night with the sun and moon and starts but other than that there is nothing. I also have logged into multiple devices including 2 different pc's and a tablet and all log ins are the same. The problem is that the account is under my name so I can't kick the player out and refreind him since that would destry the world. I also wanted to report it since it is in beta still.

Account name : AridanteLemure1