There is a FCA group in the public schools where my children attend. Two of my older children belonged to it when they were in Middle School and High School and my youngest two daughters go to the FCA meetings now. They meet once a week and mainly pray and talk a little about being a Christian student. Once a year they have a “Meet me at the Pole” (flag pole in front of school) to get together with anyone who wants to come and pray for our nation’s needs.
It is non-denominational but definitely Protestant in nature. If I didn’t feel that my children were well-grounded in their faith, I might worry that they’d be drawn to the Protestant influence there. I think it’s good in a Public School for students to see others who aren’t afraid to identify with being a Christian.
In a Catholic School, instead of having a Fellowship of Christian Athletes ( I don’t know why it’s “Athletes” since you don’t have to be in any athletics to be involved), why not a Fellowship of Catholic Athletes? Using the same format, specifically Catholic ideas, prayers, and discussions could be used. It would be an opportunity for kids who are more serious about their faith to connect and support each other.