Helmet campaigns? Frequently, after a serious crash, cyclists, or relatives, campaign for helmets. Even if the evidence a helmet would have helped is questionable. For example a girl went over the bars of her bike and broke her neck. She was convinced the helmet saved her life while in fact it may have potentially made things worse as possible landing head first on ahelmet may cause higher forces on the neck than a bare head landing.
https://www.glasgowtimes.co.uk/news/128 ... irls-life/
Then there was James Cracknell who became a helmet advocate after his crash in Arizona.
https://aseasyasridingabike.wordpress.c ... lls-brain/
I would suggest than not riding east at dawn into a rising sun would be more effective than a helmet in his case. Along with using a mirror. I have had to ride off the road in the USA to avoid being hit by an overtaking vehicle. Using a mirror I saw it coming and could do something about it.