I've been admitted and unable to use my phone for days at a time, to ensure the cat was fed, I did one call and asked that person to pass the info to others that needed to know, I couldn't make repeated calls or answer them.
I couldn't move from the neck downward so was quite restricted so I couldn't pick up the phone. I just needed to know that someone would look after the cats, I had several people that I should have let know and that I needed a bag brought to the hospital.
3 seperate friends sent many messages asking me various questions, did I see the Dr yet, .... And got frustrated that I wasn't answering calls or messages,
I was getting medical care and tests so that was my priority and I needed someone to dial for me. I was moved to a ward and had no reception and no WiFi connection,
friends still rang many times despite knowing that I couldn't move, to ask where I was in the hospital, I was frustrated with them as it was the same questions over and over which I didn't have answers to anyway but I was glad to know that they managed to coordinate enough once they copped on and brought me clothes, toiletries, laptop with dongle to watch TV on etc and agreed to coordinate as it wasn't about them at all. It had to be prioritized, cat, hospital bag, house safe and who else needed to know.
Your sisters priority has to be herself and sometimes FB us the easiest way if all your family are on it and it saves the repeated questions that may not have answers to.