You could certainly write a drunk respond in pain, in giggles or not noticing a significant injury. If your guy truly has brittle bone syndrome, it affected his childhood (and probably one of his parents, as it's genetic)...he may have off-colored teeth and sclera and had numerous fractures and very numerous bruises as a baby. If you didn't actually mean he had the disease of og imperfecta, then he needs that arm wrestling to have been pretty rowdy to have resulted in a fracture- a clean match should not break and adult's radius or ulna without exceptional circumstances...the other person much stronger and put in a last minute twist?
On the shock question, lots of people use the term in a non-medical sense even attempting to apply it to someone feeling ill, saying the person's going into shock...tho it does not meet the medical def of shock ( hypovolemia, whether neurological w/ vaso-dilation, hemorrhage or dehydration, whatever, causing dropped BP, oliguria and altered mental status) you can certainly have someone remark that the char is going into shock...heck, someone certainly would, even tho they were not using the term medically.
Have fun with it--sounds like you are.