"Attitude of nurse"

I will be making a more formal complaint by the attitude of a paticular nurse in ward b8, my brother had a quadruple bypass and is still in hospital. A paticular nurse was very rude and abrupt whilst speaking with him. They spoke loud enough where other visitors could hear confidential information about my brother and all because he asked them to come back in ten minutes as visiting times were to finish and he would take his medication then. They assumed he was refusing medication all day from "what they had heard" either in handover or corridoor chit chat however at the time of that previous discussion there was a witness to say that was untrue. They spoke to a distressed adult as if he was a winging child and i feel that was disrespectful and unacceptable.