So what happened to him?
I haven't paid much attention to the recent research on helmets -- at some point I decided I'd wear mine most of the time, not make a fuss about those who didn't, and worry about helmet laws as they came up -- but their effectiveness seems really hard to tease out. Anecdotes like yours (however it turned out) are at best a starting point. The best I think anybody has been able to do is show that they seem to provide some *net* benefit toward head trauma in low speed cycle-only crashes, but that the overall safety benefit it swamped by proper riding technique, which includes staying away from car doors. Which should illustrate a problem with most bicycle lanes.
The interesting thing about the helmet debate is how much invective gets poured on anybody who suggests that bicycle helmets are less than all that, or opposes mandatory helmet laws. This appears to be one of those Anglospheric things, most everywhere else only roadies wear them. One unfortunately effect of the emphasis on helmets is that practically every news report of a cycling fatality will mention whether or not the cyclist was wearing one, effectively shifting the blame for the results onto the cyclist, regardless of the circumstances.
-- Andy