Entering Nether Portal crashes game/cannot get back into game

In our realm, my son's character entered the nether portal and it crashed the Minecraft program to desktop. Now when he starts minecraft and clicks the realm button, it starts loading but then freezes and that's it. Can't get in. We tried destroying the portal, recreating the portal, uninstalling the game, reinstallng the game, updating video drivers.

So then I tried to go through the nether portal and the same thing happened... it crashed the Minecraft program to desktop. Now when I start minecraft and click the realm button, it starts loading but then freezes and that's it. Can't get in.

There is no error message, it just freezes and crashes to desktop. This started happening for us yesterday, March 31 late evening mst.