I think that telling them was right. I remember when my Aunt was taken to hospital, and no one told us. She was Mom's sister, and she died from an anuyerism, while in Hospital. Mom was devastated, it coming as a total shock to her, not even knowing she had been sick, let alone in such a condition.
Even when her time was drawing close, she still felt angry, hurt at how they had ignored telling her, reminding me to make sure I let my Cousin know, when her time came.
To be blunt, it pissed me off too, to have to calm her down, years, and I mean years, after the fact.
So for me, you did the right thing, and if she does try to bulldoze in, well ban her from the room. But that is just me being an ass. It infuriates me really, at how some suddenly show up to tell us what we should or shouldn't do in caring for a loved one, while they are rarely around when the commode needs emptying, or one has to try to figure out how to pay for the weeks meds, that Pharmacare doesnt cover.
Anyhow, take care, try to stay calm and if you need to vent, let loose, whether to the four walls, or here. Its good to release when you need to.
hugs