Just thought, head injuries, not wearing a helmet that there might be a connection. That's all. Simple.
Seen (had) enough dented, split, damaged helmets over the years but no damage to the head inside to realise it's a no brainer (pardon the pun) to wear one when riding.
Someone fell off a bike whilst not wearing a helmet and suffered a fatal head injury. It's very sad, but it tells us nothing.
Do we know from that story - in the time between that poor child's death and the death of the next child from cycling accident related head injuries - how many children died from head injuries involving cars? Or garden trampolines? Do we know that a helmet would have saved him/them? No we don't and no we don't.
I know of someone who suffered permanent debilitating brain damage as a result of standing up underneath the corner of a kitchen cabinet door but I don't use this to support my belief that people should wear protective helmets when putting the dishes away.
This is like trying to explain the concept of climate change to someone who is peering at the sky through a letter box.