My mum went a bit like this when my dad was in hospital recently. She would text me about 5 times a day then phone me at night, usually just to tell me that nothing had changed since the last time we'd been in touch. Obviously I was worried too and wanted updates but there was a stage when there was just nothing happening.
If I didn't answer my text within about 15 minutes she would text again ,and if I didn't answer that she would start calling the house phone.
I think it was just nerves and anxiety and because she was worried about my Dad she became scared that something was going to happen to one of us too.
It does get too much and it's hard to set boundaries without hurting her feelings. When she would text in the afternoon I would thank her for the update and say that I knew she had a lot to do so she didn't have to get in touch again that day unless something changed, or say that I had promised to take the girls to the park/ swimming etc and wouldn't be able to answer my mobile and wouldn't be at home. I always ended by promising to call her to catch up on everything as soon as I could.
I found that this gave me back some control and as long as she knew where I was and that I would be in touch soon, she backed off a bit.
Hope this helps. x