I met this woman in Kansas City who was married to her first husband, and they had two very young kids. His friend came over to show off his new motorcycle and the woman's husband took it for a short spin. No helmet.
During the ride, he saw a cop, panicked because he had no license and made a quick return to the house. Coming around a corner, he hit some gravel in the road, went into a neighbor's yard and hit a tree.
The woman's husband lost both legs, one arm and was severely brain damaged as a result of his accident. So here she was, young, uneducated, two small children to raise and a disabled husband to take care of. She remained with him for the next 5 years, going to night school, supporting her kids, and taking care of the man who became increasingly verbally abusive to her and the kids. Eventually she had to have him committed to an institution. She has since remarried and is now very successful, but her life was destroyed by her husband's choice to ride that bike with no helmet.
I have buried a few friends who did not wear helmets, one was a 400 lb, 7' tall man who was buried in a standard 6' box. If you ever have to see something like that, it rips your heart out. I was the only one who went to the funeral on a motorcycle (It was my only means of transportation at the time).
The other friend was a twin and his sister found him after he went head first into his Mothers car as he rounded the corner to their home and hit some oil in the road. His brains were scattered in their front yard. Her response to losing her Brother was to become an alcoholic and drug abuser, and she deteriorated pretty fast afterward. I do not know if she is still alive now or not.
No matter what anyone says, helmets save lives. If they didn't professional riders would not be required to wear them at all times.