I’m in that situation. I think it depends on the relationship you have with said parent. Because it’s not only you, but your whole family that have to take part in looking after, or tolerating, the elderly parent. Also consider the feelings of the parent, especially if they are developing dementia. It’s a child’s obligation but they’re are considerations to be made in reality.
I don’t think there should be a second thought. Look at it this way did they think twice about taking care of you? There is nothing to think about if anything everyone should pitch in and make it a family thing take turns helping each other.