I think all these details are relevant:

Lack of lighting is obviosly a high risk factor

SUV collisions are statistically more likely to kill pedestrian and cyclists than are those involving real cars.

SUVs are badly compromised in handling and braking compared to real cars.

Unless we know that the cyclist did not suffer a head injury, I would not dismiss the "no helmet" bit as irrelevant. Helmets are good to have on when you sail over the car and land flat on your head. Unless you wear one on each knee, they will probably not help much in a typical fall.

Paul