He got beat up.
He confronted his parents and told them about his ambitions, and as a result, his father made absolutely sure he understood the weight of his decision.
Still, it was a gesture of concern.
It was a show of concern, because no matter how unaware they were about the world outside of their village, they were more than aware of how cruel it could be.
They didn't want their innocent son to be corrupted by that world. They didn't want him to disappear and never be heard from again. They didn't want him to become a sacrifice for those people who regarded human life as nothing.
But Alexander was determined.
The look in his eyes was proof enough that his mind wouldn't waver, and with no other choice, they accepted their son's dreams.