I’m sorry to hear about your brother! I hope he is doing well 🙂 Your brother must have been involved in some sort of accident. When a spine experiences an impact, if the impact is strong enough it can damage the vertebra. The vertebra then fractures (breaks) and this usually results in a decrease in height, especially in the front part of the vertebra. That is why its called vertebral compression fracture, or compressed vertebra. The vertebra literally compresses into a smaller space as it fractures. I hope this explanation helps!