I'm sorry to hear about your friend.
I grew up in England. From the time we could walk we had it hammered into us: "Look right, look left, look right again. If the road is clear Walk across."
Doesn't work so well when traffic is on the right hand side of the road.
I was not as unlucky as your friend but for years after arriving in the US I has a lot of "could haves."
My wife's niece did her semester abroad in England last year. My sole piece of advice to her was to memorize that ritual. (Well, other than "Get your face out of that phone!")
She came back in one piece. I like to think I contributed a little tiny bit. Traffic in England is fierce.