Sorry to hear about your friend.
I've personally decided that my skull and its contents are worth protecting, and worth protecting well, and feel naked riding without a good and properly-fitted helmet.
I've personally decided that my skull and its contents are worth protecting, and worth protecting well, and feel naked riding without a good and properly-fitted helmet.
Even if you do get injured, I'd think it would be far less likely to be the kind that puts you into a vegetative state.