My brother, my friend, and I were on a private multiplayer server I set up. We finally gained enough obsidian to make a Nether Portal. We went in and immediately started exploring. While the two went somewhere, I attempted to build a bridge but was killed by a ghast. When respawning (The game also can't find my bed for some reason), I walked towards my house. My friend decided to check on me, and we noticed that his house was demolished. We were very confused and sad because of the amount of work put into the construction. It seemed like as if a ghast must have exploded it. Can anyone solve this mysterious case?
It was not griefed as the house that was destroyed was my friend's house and my brother was still in the nether. I was the only op in the server. My brother and my friend were not. There was a fireplace, but my friend left it unlighted.
You have to sleep in a bed before you will respawn there. It is best not to have it against any walls.
Was the house made of wood? Lightning, or possibly underground lava nearby, could burn a wooden structure. Lava can start things on fire a number of blocks around and above it, even through solid stone blocks. If he was storing lava to make the obsidian, or had a lava incinerator for trash, that could explain it.