Thanks for being so open with your feelings about your friend and your new concerns about cycling. We all gain from each others' life experiences here and I've shared my own anguish like it was among friends. Feel free to continue as your friend mends and even once he gets back on his feet. He sounds blessed to have so many people in his life who care and look after him.
It sounds as if you are carrying a heavy weight of thoughts and emotions, having known him so strong before and now seeing him bruised and broken and in so much pain. That mental shock can also be felt physically so take care of yourself as you walk along with him through his ordeal.
It took me a long time to feel as comfortable riding in traffic as I do now. In the beginning, I felt trepidation every time. Now, it hardly bothers me at all -- it feels like a challenge and I always stay alert, but I'm no longer afraid. And that's a good reason to pay even more attention. When a bike and a car/truck collide, the car/truck always wins.
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Specialized Roubaix Expert
Surly Long Haul Trucker