How do I convince this stubborn person?

Why force him? He has his interests and you have yours. He doesn't have to agree with them. There's no reason he HAS to like what you like any more than you have to like what he does. Let it be.

In the 1940's and 1950's science fiction thought that man will land on the moon one day. Since man has landed there3 times now (the Chinese just recently), it is now NON fiction, the science part of science fiction has come true.
Point that our to him.

Just pity him. He doesn't know what he's missing. There's no point in trying to change his mind. Do share the best of what you love, but when it comes right down to it, you can't change a person's tastes.

Do feel free to act superior when he tries to guilt-trip you. "Oh, yes, but isn't that sort of stuff so cold? It really doesn't have a lot of relevance to modern emotional life, does it? Blah-blah-blah, ****-****-****, but as long as YOU feel you are getting something out of it, that's what's important." Smile sweetly.

And be proud of what you read. If you like it, that's what's important.

Mind your own business. Why are you trying to mess with what they like, anyway? Leave them alone.

You don't. You have your tastes and he has his. Leave him to like whatever it is he likes.

Yeah I had the same problem with my sister. I just kept telling her that she has never even tried to read fantasy so she has no valid reason for saying that she hated it. Hope this works for you.