I am an avid cyclist and your friend has my prayers.
Was he wearing a helmet? Riders can still get hurt with a helmet, but a helmet really helps. I am constantly amazed when I see riders without helmets.
I wasn't there when it happened and don't know all the details. But I know that it was his habit to wear a helmet. Everytime I saw him on his bike or about to get on his bike he had his helmet on.
But it was a really nasty fall. As it was described to me, something went wrong with his front wheel while he was going really fast and he went over the handlebars. So maybe it wasn't enough to have a helmet.
BTW, I'm glad you brought up the subject of helmets. This is the second case I know of somebody being severely injured in a bicycle accident. The first was someone I only knew indirectly, and he is a vegetable now.
Hopefully this posting will get more cyclists to wear their helmets.