In a fight with a giant skeleton he died then I did. I woke up on the slab but he was gone. I have had a look around the rough location where I think he died, but I can't see any trace of him.

Is there an easy way to locate lost members?

You don't see bodies of dead party members lying on the floor, it's assumed that you drag them along.
As long as they're still in the party (the symbol for the dead character still at the bottom beside your character portrait) there's a way to revive them.
Items in inventory are dropped on the ground where they die.

Thanks. Was able to revive him eventually.