I too am a habitual seatbelt wearer. My dad never was, until he got a ticket. "I don't plan on getting into an accident, so why should I?"
A friend of mine got into an accident on a scooter while visiting Bolivia in the middle of nowhere a few years back. Shattered her shoulder and her jaw. By some miracle, she and her sister managed to get to a hospital and she's made an amazing recovery. I wish the same for your friend.