AITA or expecting my sibling to show me the same courtesy

I have a lot of siblings. Our mother is 83. Many of us talk to our mom at least on a weekly basis and would probably be concerned if our calls suddenly stopped getting picked up. I texted all of them the same message about our mom being out of phone service, and would expect them to do the same if they had that information. All my siblings just responded with a thumbs up, or a "thanks!" Not this one. It always has to be a thing with this sibling.