Seriously? Brain concussion. If you're hit hard enough to break the orbital bone, which is extremely heavy, you brain is rattling around in your skull like a pair of maracas.
Uh. You are wrong. The floor and medial wall of the orbit is paper thin ( lamina papyracea in Latin). That’s what breaks in an orbital floor blowout fracture. The only way it might be fatal is if you got an infection that tracked into the CNS.
Now any blow to the head, in the right circumstance could lead to an intracranial hemorrhage. But that’s not directly associated with an orbital blow out fx.
A brain concussion is totally different from an orbital blowout. Even so, I never heard of someone being killed by a concussion alone.