Indeed! The halo saved his life for sure. The race commentators were talking about there being a weak point in the barriers at that point for some reason. I think part of the problem was the angle that the barrier jutted out to create the service vehicle opening.
Yeah I think the fuel tank sits behind the driver and in front of the engine. They are a bag or bladder type tank these days. They are meant to be resistive to being punctured, but it was probably torn open by the impact. Apparently the driver was subjected to about a 53g deceleration!