In l’amour with a Gay guy...?

This girl I know have fallen in l’amour with this new gay (please don't get insulted when I use that) type. He's pretty cute, so I'm not surprised she likes him, I didn't know he was gay before he told me.

It didn't surprise me though, but the question is, how should I tell my friend who "hates fags"?
Should I just let it be as it is, ou hope that he tells her himself?