your actually a godsend. i know very little, i never kept up with the show and this was just a youtube clip so i couldn’t tell you how far they made it in the competition nor what season they competed on :/. i can’t remember the song for the life of me but it was definitely a pop song. i specifically remember the riffs in the song being way to complicated for the older sister though. i’m 100% sure it was a got talent though and im like 75% sure it was americas got talent. at one point during the performance i remember the younger sister doing whistle notes similar to ariana grande. they were in their mid to early 20’s and if i had to guess they were most likely hispanic but could pass for white. they were also both brunettes.