That's not cool. I would think that he could simply state that he is teaching what is known about the science of biology and the conclusions drawn by men noted in science (who obviously progressed further in various specialties than he did), though his personal conclusions may not always coincide. However, knowing that our knowledge of science is always progressing, he is happy to keep on learning!
Then teach the class what he is required to. Keeps him honest, but truly, if he has so many objections, he has no business teaching the class in a public school.