My (23M) brother (28M) keeps telling me to do OF

It makes me uncomfortable. He has no reason saying that, I could be talking about what I want to do with my career and he'd just start telling me to do OF. I've told him to stop, but he's been saying that for years. Maybe he's just trying to annoy me because he knows it pusses me off, but I find his comments inappropriate and weird af. I'm genuinely disgusted. It makes me so mad and annoyed, I can't just ignore it. This CANNOT be normal, right?