buddy of mine, total fitness nut and a bad ass on a bike --- he died about two weeks later from a bike crash ---
got side swiped from a car, hit pavement --- got up walked away.. thought he was fine... didn't think much of it.
died at work, at his desk, from a brain aneurysm... left a wife, 3 year old daughter and a bun in the oven that day...
sounds like what happened, he had a concussion and didn't take it easy - so, it's not like he died there on the spot when he got hit. he was just a bad ass on a bike.. commuted to work pretty much every day --- he did wear a helmet when mountain biking but wasn't wearing one when he got hit by a car. and I should note -- again, it was a very small incident.
concussions can kill ya if you don't take it easy for a good long time. ask any Dr that.. that's why the NFL is so serious about them these days
all it takes is one good smack on the ground... it really doesn't much. drives me crazy seeing parents riding with their kids on the bike trails --- kids have em, parents don't... WTF
just as bad is young kids not wearing helmets correctly, often pushed way back which does little good.
ugh, I could on and on about this.
www.youtube.com/watch?v=gxOeKwVVCVg&app=desktop