I am trying to find the name and author of a story that I read during my teenage years. The story involved a family of descendents from another planet. The story involve a brother and sister. The brother was in his late teens. The sister was younger and was a "sensitive". The family live on the outskits of town. As the story played out the mother was hit by a car and died and the brother felt as if he needed to take his sister to find what was left of their people. They did find them and were accepted into the community.
I knew I'd get there originally, although it took me a bit more than a minute.
This is Gilead, by Zenna Henderson. It's part of a larger series, The People, about a race of aliens who are forced to leave their home planet and settle on Earth.
The mother of the children in this story (who are called Peter and Bethie, by the way) was separated from the rest of the People somehow, and married a human. They inherit some of her powers, but not all: for instance, as I mentioned in the comment, Peter can levitate but not get down; Bethie can "platt sunlight" which is the secret to getting down, but Peter can't even grab hold of it.
After their parents' death, the children go in search of the rest of the People, and do eventually find them.