“It was a good thing we were in my van. While we love Betsy’s Prius, this would have been a different story if we had been driving it.”
I’m not sure this is true. Sure, your van is heavier, but what matters in a collision is how quickly the human brain is accelerated, and what parts of your body impact the solid parts of the vehicle. Newer cars with lots of airbags and well designed crumple zones may be better than older, heavier cars, depending on the type of crash. I believe side-impact crashes like this are tough to protect against, because there is less space between the edge of the car and the humans inside.

I hope you both a speedy recovery! Don’t give up on the police, you deserve to find out what happened with the person who caused this crash. Even if they don’t press criminal charges, it might be worth a civil case for lost wages, medical bills, etc.