Horrendous :cry: Poor bastard didn't have a chance with a rock that size.
I sat next to my mate after the car had crashed on the way to the crag and had to sit there holding a huge flapper that had his ear on it back onto his head in the vain hope it would help, but of course it didn't and he died that night. It was a long time ago now but it still hurts to think about it in any detail.
I don't think anything can prepare you for violent death of a friend, especially when it come out of the blue like that - as you say Dave, all you can do is hope it never happens to you.