Any younger siblings taking care of an older one?

For context, my elder brother has a condition that developed recently, and he’s become more… incapacitated? I guess maybe I’m overthinking things, but I do notice a shift in our family dynamic. We don’t have a large year gap, just two or so years in between us, and I’ve recently found myself being in more mature positions in our household, and a lot of coddling for my brother. I mean, even after his symptoms had settled down, I see no signs of returning to the old dynamic.

Anyone else in this situation?