One In Homeschool, One In Traditional School

Does anyone else have one or some children that also go to traditional school? My daughter does and she thrives there. The problem I'm having is that she is a Junior, which is right on track for her, and my son is a Sophomore, which is two years ahead for him. It frustrates her, and she is always saying that she doesn't think he is "really" in 10th grade because he hasn't taken some class that she feels he should have to be a Sophomore. When I try to explain that homeschool requirements are a little different and that the same school board that oversees her public school education also oversees his homeschool education, she just gets more frustrated. Any ideas on what I can do to help her understand better?