Well he was essentially chosen as breeding stock to produce the most powerful alpha possible, so I don’t think the royal family is concerned with birth control. If anything, they would probably prefer it if the prince knocked him up and marked him before he knew anything so that there would be another aspect trapping him in the palace.
I get where you're coming from...But sex education is not just about birth control??? And since this is omegaverse, maybe more on the topic of second genders, pheromones, etc...
That’s true, but the less he knows, the more he will have to rely on the prince. Everything he knows so far has been spoonfed to him by the prince at his convenience. As a rule, it’s easier to control and manipulate people when you are in control of the information they have access to
Instead of etiquette, shouldn't he be learning about sex education, specifically about being an omega.