Michael Schoch, Answers questions on Noodle
This is an excellent question for a parent to ask and one with which both students and parents alike sometimes struggle. I would recommend looking at previous questions and answers on Christopher Columbus High School's Noodle profile to get a sense of what other students think the environment is like. After that, I'd suggest calling the school at (305) 223-5650 and simply being honest with your concerns. The school's staff may be able to tell you if there are other parents with similar concerns and what they've done/what's happened.
Before you call or visit the school, read this article for an idea of what to look for in terms of LGBT acceptance. The article contains links to other resources as well.
Good luck and feel free to ask more questions any time!