I will be surprised. First, I will ask him why does he hate Bitcoin, what are the reasons. If I think that it's not sufficiently good, I will start explaining to him what Bitcoin really is. How generally it works, how Bitcoin had helped a lot of people, its benefits, advantages, and other things I know that will convince him. But if he still insist his hatred about Bitcoin, then fine. I did what I think a Bitcoin user like me should do. The repentance is in him.