Legal question about Antique vehicles and the seat belt laws

I wrecked a 71 D100 on black ice, pegged a guardrail head on the interstate, I was wearing a lap belt, just broke my nose on the steering wheel, did not need medical attention, my 3 year old son was sitting in the middle, buckled in, he was fine.
My wife did not have her seat belt on, she leaned over our son to protect him, her head it the windshield hard, she was black and blue for over a week on her chest and ribs from the metal dash.