Child taken to hospital after crash on BMX (From Worcester News)

Wear a helmet.... no chance. There has been some research recently that has shown car drivers give you a wider berth if you don't wear a helmet. This will do for me.
If cyclists are to wear helmets then drivers also should as car accidents cause head injuries to car occupants, collision speeds are higher and there are plenty of things in a car to hit your head on.

I've heard about the above research too - However I'd still prefer to wear a helmet so that if worst came to worst (which it has done in the past) at least I'd have some sort of head protection on.
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It's not only drivers leaving too little room when overtaking - it's also the ones who fail to spot a cyclist when pulling out of / in to a junction. I have the x-rays to show for my various run-ins with such people!
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I hope the lad gets well soon, and I hope that this doesn't put him off cycling.

I grew up crashing bikes... various bones got broken and lots of flesh was scraped off by tarmac and I did whack my head a few times, on and off road, without a helmet on, most recently 2 years ago at 30 mph in a time trial when I hit a cat, it survived..

Usually what happens is the shoulder gets it worst and you might get a scrape or bump on the head but unless you are unlucky enough to hit a kerb or post you are very unlikely to sustain severe head injuries on a bike.
Severe head injuries can occur wearing a helmet due to the brain rolling in the skull, the helmet changes the head shape and can cause these injuries that would not have happened otherwise.
I am in no way saying that helmets have not saved lives and prevented brain damage but they should not be seen as the great saviour and certainly there should not be legislation to enforce the wearing of them.
I would however support legislation that meant that very young children being carried on bike seat wear them as this age group are not so good at landing or protecting themselves in a crash. Most parents already do this though.