It doesn't seem fair, but it's more than possible that he's got another one on a different vertebrae…or something else going on in his spine.

Might be time for another image, or at least a visit to the ortho.

I was recently surprised to learn that compression fractures can happen without a fall or other dramatic injury. (My mom has one of these types.) Your dad could have one and not even know it.

Then, in the case of my mom, she broke another vertebrae during a fall but didn't mention it. Despite massive bruising she forgot the whole incident.

My mother declined surgery for her broken T11, which is risky at her age and condition. (She would have needed a complete replacement of the vertebrae from the thoracic side, which involves cracking her open, collapsing a lung, and other niceties.) The doc is following her with regular imaging…every 6 months. A lot can change in 6 months apparently, and a change in leg sensation or function is one of the indicators we are supposed to be on the look out for.

Good luck...