Stay out of it, especially since you did not witness anything. Progress notes are legal documents. Most likely case, no one reads your note and no one looks further into this. Best case, the nurse is some combination of evil/incompetent and did this and then during the court case, your documentation serves as a minor piece of evidence. Worst case is you rub the nurse the wrong way when they read your note, talk to their nurse manager, who then talks to your attending who calls you and tells you to addend your note which makes them second guess your documentation.
You should document:
Document time and patient's chief complaint which lead to XR being ordered. "XR demonstrates radial fracture which per radiologist appears relatively acute. Etiology unclear. Son had concerns regarding patient's medical care. Directed son to XYZ to voice his concerns".
You should do the following:
Give son an avenue to voice his concern/complaint (Ombudsman, whoever he wants to talk to), notify the attending that this happened when there's time as risk management needs to be involved, and lastly notify the nurse manager exactly what exactly the son said without any color commentary because that's all you witnessed and are therefore responsible for. They're the ones with best vantage point to interpret what happened and are responsible for it as they keep tabs on the nurses and patients on the unit and know how to best handle situations like this.
Also, not to echo what's above, but I fail to see how the twisting motion involved in inserting an IV could fracture a bone. The soft tissue (ligaments, joints, etc) would give away first so that would present more like a dislocation.
