Could it be that he could have survived the accident had he been wearing a helmet?
I know having a helmet saved my brother's life when he has taken a spill (on more than one occasion) and it also saved the life of the guy that ran into the back of his car while he was stopped at a stop light. It looked like someone shoved a bowling ball into his trunk. In my mind it's not an irrelevant statement, if it could have made a difference.
In Arizona, adult cyclists are not required by statute to wear a helmet. Whether they should or not is debatable and the epidemiology of helmet non use remains unresolved. In practice, it seems to be an individual choice and, yes, in hindsight, individuals sometimes seem to make bad choices.
Perhaps you can find a Tucson Police Department media release regarding a fatal car-on-car or car-on-fixed object accident in which it is noted that the motorists and passengers were not wearing helmets or the motor vehicle(s) did not have airbags.
Sorry to learn of your brother's unfortunate spills.
Thanks, part of the dangers of being a bicycle commuter in San Francisco (slick rails, slick cobblestones, etc), but he still rides and takes the train to work every day.
I'm guessing the non-helmet epidemiology would be similar to motorists not wearing their seatbelts. Seatbelts weren't always required by law, so maybe when enough people die without helmets on, there will be a change in behavior.
Mention of airbag deployment, or not, has become an item of note in some reports, but maybe not the TPD press releases.