I live in California and my son, 12 years old, attends public school. He is gifted in track and basketball so we keep him in the public school system so that he can compete. At home, we counter teach him in all the subjects that he “must” learn in school. He knows the truth and he also understands what the schools are trying to do. I am proud that we are raising a very smart conservative. I hope that, someday, maybe his children will be able to go to school to learn the truth.
Seriously, if you throw him in the shark infested waters, he has to know about the sharks* and be armed (with the truth).
Realize that the teachers have them for 6 hours a day - but if he doesn’t view them as benevolent authorities, that will help.
*Secular Humanists are Revolutionizing Kids [in] Schools
best I could come up with on short notice