I don't think so.
If this has hit his neck, I'm assuming directly on the pulmonary artery, then the newer helmet wouldn't have protected him
Not sure if that's a typo MU, but the pulmonary artery is in your chest. Not being a smartarse, but this is what I believe happened.
The ball has hit his neck/base of skull at approximately the C2 level. At this point the vertebral artery exits the relative protection of the verbal column and exits laterally before curling over the C1/2 vertebrae, before re-entering the skull base. It then continues for an inch or two before joining te other vertebral and becoming the basilar artery. This artery supplies the PICA and AICA arteries. These are two important arteries that supply the cerebrum.
I think that the trauma of the impact has cause the vertebral to be ruptured or temporarily blocked, which then cause him to black out and fall forward. At this point in time we don't know as joe public, what the extent of this injury is and therefore the nature and severity of the brain injury that has resulted.
One can only hope that blood supply to his brain remained constant and/or been restored in a time frame that will reduce any further and long term effects.