If he is still making this much fuss because of something that happened to him 14 years ago, I would speculate that that either:

a) Your DH needs some degree of counselling to deal with this past trauma.

b) Maybe this has nothing to do with the bike, and everything to do with control.

Yeah, riding a bike is dangerous. So is driving a car, walking across the street, and so many other things associated with living. He needs to get over it.