Two siblings with OI

One of my students (8th grader) and his sister (11th grader; my sister's best friend) has OI. A couple of months ago my student was playing in school and broke his knee. He was rushed to the emergency room and had a long recovery. His knee is still weak and he walks with a limp, but now he no longer plays as much as he used to and he's afraid to play sports for the risk of breaking another bone. His sister told me that when he was younger he fell out of the bed when he was a toddler and suffered a fracture and his mother was almost arrested because the doctors thought that he was being abused by his mother and father. When they ran some additional tests they found out that he suffered from the Osteogenesis Imperfecta disease. I do not know what type he considered but I do know that he needed to go to the hospital to receive calcium because his levels were extremely low. I would like to talk more with them to see how they feel but whenever the subject is brought up they don't seem to want to talk about it, so I leave it alone but they know that if they ever need to talk to me about anything they are more than welcome to talk to  me at any time.