The Catholic High School in my area is $12,000 dollars a year for tuition,plus books and uniforms.
The Catholic School in your area might be worse than the public school, as it may be teaching lessons antithetical to the teachings of the Church, but in the name of Catholicism.
The Catholic HS in my area teaches a classical education by teachers who do not go against the teachings of the Church.
How do I know? I ask the kids every day what happened today, and eventually I get them to talk. I never betray their trust for any reason, for fear they won’t talk to me again - if I do it’s CIA level stealth. And I make it my business to know the basic tenets of the Church.
I use their college fund to send them there and they know their college is going to be paid for by them.