I saw them about 2 years ago here in Chicago. There was a pre-concert talk in which they talked about themselves. At that time the youngest boy was 17, and still in high school. The others were either graduates of Julliard, or enrolled. All had full scholarships to Julliard.
They started playing when they were 3, and as each kid grew, they needed another piano in the house, and they ended up with 5 pianos (in the bedrooms!). No, they were not rich, their parents bought cheap upright pianos (all they could afford). There would have been no way for them to go to Julliard if it weren't for the scholarships awarded by the school. They said it's easier to play ensemble when they DON'T see each other, by the way.
The picture doesn't do the girls justice. They are all gorgeous, lithe and sweet. All the kids are well-adjusted, and happy. There was real joy in the way they played piano.
The program was:
1) Concerto for 3 pianos by Mozart (the 2 boys and the youngest daughter played).
2) Concerto for 2 pianos by Poulenc.
The concert was outstanding, and there was a lot of musicality going on. They were not showy or "hollywoody." Thoroughly enjoyable.
George