Been there, done that. Thankfully he was OK. A lot of streeters end up dead that way.
I was out riding my Ninja 650 one night. Stopped at a 4-way stop. Saw there was a vehicle coming up from behind but didn't realize how fast it was coming. I had just started letting off the clutch and rolling the throttle to move on when I heard tires screech and, BOOM, I was hit.
Suffice it to say, my bike was messed up and I was messed up. Luckily, the bike just needed some parts and was good to go. I was lucky as well. Ended up with only a very sore and bruised lower back and strained ACL and MCL in my right leg. Thankfully I'm a ATGATT kind of guy and it saved me some pain for sure!