Ah, hospitals. I feel for you.
I haven’t read the comments here yet, but scenario 1 and a modified scenario 2 in combo sound like the best approach. DO NOT TELL PEOPLE TO CALM DOWN, IT WILL ALWAYS MAKE THEM ANGRIER. The best way to do it IMO is to model the behaviour you want to see - remain calm. Explain (to the degree that you’re authorized to as a nurse) why they can’t do the thing, and the potential outcome of doing the thing. While trying to calm them down, have the more vulnerable target disengage and make the call to security. Remember that your duty is to your patients’ health and safety - make it as clear as possible that you’re not doing this to be a power-tripping douchebag, but to make sure their father gets the best possible care they can so they can go home ASAP.
My work experiences are not exactly the same, but similar in some respects. I’ve found it useful to consider the following - in a healthcare-related scenario, the person who is super pissed and aggressive is usually more scared/freaked out than angry. If you address the fear they will usually calm down pretty quick (or at least the anger turns to other, less dangerous expressions of fear).
Does your hospital/union offer any training on descalation techniques? They’re not a cure-all but it’s vital stuff to know in a high-tension environment like a hospital.
Edit: Misread the OP and thought patient was the daughter of the aggressors, fixed to say ‘father’.
All I remember is that it ran Windows 3.1 and had a ‘Turbo’ switch on the front. To this day I have no idea what that did, but was told not to touch it.