Dave glad your Dad is safe and alive. It will be a long road for his bones to mend, but like you said, thank god he's alive. When I was a teenager a friend of mine was riding dirt bikes with his Dad. A guy was out in the forest trimming trees near the road they were on, as the came ripping around a turn they heard a tree snapping and falling, both gassed it hard, the treecaught his Dad with the tree top branches and knocked him off his bike. He said his heart nearly stopped as he dug underneith the branches for his Dad. He also said he knew his Dad was ok, because his Dad's first words were, "god, so that's how a fly feels right before the end!"
We will pray for a fast and full recovery for your Dad.