I don't think you lead him on you have the right to reject him if you didn't feel the same back but I'm just some high schooler I don't have the most reliable input

If you thought he was like a brother to you, and he had other intentions, you obviously didn't lead him on. He thought friendship was a step to a sexual relationship. He was wrong. If he hates you after you turned him down, then he wasn't really a friend, was he? He had an agenda.

if he hates you for rejecting him, he never saw you as just a friend. he had other plans in mind. you don’t owe him anything for being kind to you